Method and apparatus for allocating wireless resource in order to prevent interference in wireless lan

ABSTRACT

Disclosed is a method and apparatus for allocating a wireless resource in order to prevent interference in a wireless LAN. A method for allocating a wireless resource in a wireless LAN may comprise the steps of: allocating, by an AP, a plurality of wireless resources for a plurality of STAs included in a BSS, in the entire bandwidth, respectively; and transmitting, by the AP, a PPDU to the plurality of STAs through the plurality of wireless resources, respectively, wherein each of the plurality of wireless resources is a combination of a plurality of wireless units defined in different sizes on a frequency axis, and each of the plurality of wireless resources can be determined in consideration of the size of the bandwidth of at least one STA supporting a bandwidth smaller than the size of the entire bandwidth from among the plurality of STAs.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to wireless communication and, mostparticularly, to a method and apparatus for allocating a wirelessresource for the transmission or reception of data in a wireless LAN.

Related Art

Discussion for a next-generation wireless local area network (WLAN) isin progress. In the next-generation WLAN, an object is to 1) improve aninstitute of electronic and electronics engineers (IEEE) 802.11 physical(PHY) layer and a medium access control (MAC) layer in bands of 2.4 GHzand 5 GHz, 2) increase spectrum efficiency and area throughput, 3)improve performance in actual indoor and outdoor environments such as anenvironment in which an interference source exists, a denseheterogeneous network environment, and an environment in which a highuser load exists, and the like.

An environment which is primarily considered in the next-generation WLANis a dense environment in which access points (APs) and stations (STAs)are a lot and under the dense environment, improvement of the spectrumefficiency and the area throughput is discussed. Further, in thenext-generation WLAN, in addition to the indoor environment, in theoutdoor environment which is not considerably considered in the existingWLAN, substantial performance improvement is concerned.

In detail, scenarios such as wireless office, smart home, stadium,Hotspot, and building/apartment are largely concerned in thenext-generation WLAN and discussion about improvement of systemperformance in a dense environment in which the APs and the STAs are alot is performed based on the corresponding scenarios.

In the next-generation WLAN, improvement of system performance in anoverlapping basic service set (OBSS) environment and improvement ofoutdoor environment performance, and cellular offloading are anticipatedto be actively discussed rather than improvement of single linkperformance in one basic service set (BSS). Directionality of thenext-generation means that the next-generation WLAN gradually has atechnical scope similar to mobile communication.

When a situation is considered, in which the mobile communication andthe WLAN technology have been discussed in a small cell and adirect-to-direct (D2D) communication area in recent years, technical andbusiness convergence of the next-generation WLAN and the mobilecommunication is predicted to be further active.

SUMMARY OF THE INVENTION

Technical Objects

An object of the present invention is to provide a method for allocatinga wireless resource for the transmission or reception of data in awireless LAN.

Another object of the present invention is to provide an apparatus forallocating a wireless resource for the transmission or reception of datain a wireless LAN.

Technical Solutions

In order to achieve the above-described technical object of the presentinvention, according to an aspect of the present invention, a method forallocating wireless resources in a wireless LAN may include the steps ofallocating, by an access point (AP), a plurality of wireless resourcesfor each of a plurality of stations (STAs) being included in a basicservice set (BSS) within an entire bandwidth, and transmitting, by theAP, a physical protocol data unit (PPDU) to each of the plurality ofSTAs through each of the plurality wireless resources, wherein each ofthe plurality of resource units corresponds to a combination of aplurality of wireless resource units each being defined to have adifferent size within a frequency axis, and wherein each of theplurality of resource units is determined by considering a bandwidthsize of at least one STA, among the plurality of STAs, the at least oneSTA supporting a bandwidth having a size smaller than that of the entirebandwidth.

In order to achieve the above-described technical object of the presentinvention, according to another aspect of the present invention, anaccess point (AP) allocating wireless resources in a wireless LAN mayinclude a radio frequency (RF) unit transmitting and/or receiving radiosignals, and a processor being operatively connected to the RF unit,wherein the processor is configured to allocate a plurality of wirelessresources for each of a plurality of stations (STAs) being included in abasic service set (BSS) within an entire bandwidth, and to transmit aphysical protocol data unit (PPDU) to each of the plurality of STAsthrough each of the plurality wireless resources, wherein each of theplurality of resource units corresponds to a combination of a pluralityof wireless resource units each being defined to have a different sizewithin a frequency axis, and wherein each of the plurality of resourceunits is determined by considering a bandwidth size of at least one STA,among the plurality of STAs, the at least one STA supporting a bandwidthhaving a size smaller than that of the entire bandwidth.

Effects of the Invention

When allocating resources for each of a plurality of stations (STAs)based on orthogonal frequency division multiple access (OFDMA), sincewireless (or radio) resource units that are defined to have sizes beingdifferent from one another may be allocated to each of the plurality ofSTAs, scheduling flexibility may be enhanced and throughput of thewireless LAN may also be increased.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a conceptual view illustrating the structure of a wirelesslocal area network (WLAN).

FIG. 2 is a conceptual view illustrating a resource allocation methodaccording to an exemplary embodiment of the present invention.

FIG. 3 is a conceptual view illustrating a resource allocation methodaccording to an exemplary embodiment of the present invention.

FIG. 4 is a conceptual view illustrating a resource allocation methodaccording to an exemplary embodiment of the present invention.

FIG. 5 is a conceptual view illustrating a resource allocation accordingto an exemplary embodiment of the present invention.

FIG. 6 is a conceptual view illustrating a resource allocation accordingto an exemplary embodiment of the present invention.

FIG. 7 is a conceptual view illustrating a resource allocation accordingto an exemplary embodiment of the present invention.

FIG. 8 is a conceptual view illustrating a resource allocation accordingto an exemplary embodiment of the present invention.

FIG. 9 is a conceptual view illustrating a method for signalinginformation corresponding to RRU/IRU based resource allocation accordingto an exemplary embodiment of the present invention.

FIG. 10 is a conceptual view illustrating a resource allocationaccording to an exemplary embodiment of the present invention.

FIG. 11 is a conceptual view illustrating a method for transmitting DCtone/guard tone allocation information according to an exemplaryembodiment of the present invention.

FIG. 12 is a conceptual view illustrating a tone allocation methodaccording to an exemplary embodiment of the present invention.

FIG. 13 is a conceptual view illustrating a tone allocation methodaccording to an exemplary embodiment of the present invention.

FIG. 14 is a conceptual view illustrating a PPDU format according to anexemplary embodiment of the present invention.

FIG. 15 is a block view illustrating a wireless device to which theexemplary embodiment of the present invention can be applied.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

FIG. 1 is a conceptual view illustrating the structure of a wirelesslocal area network (WLAN).

An upper part of FIG. 1 illustrates the structure of an infrastructurebasic service set (BSS) of institute of electrical and electronicengineers (IEEE) 802.11.

Referring the upper part of FIG. 1, the wireless LAN system may includeone or more infrastructure BSSs 100 and 105 (hereinafter, referred to asBSS). The BSSs 100 and 105 as a set of an AP and an STA such as anaccess point (AP) 125 and a station (STA1) 100-1 which are successfullysynchronized to communicate with each other are not concepts indicatinga specific region. The BSS 105 may include one or more STAs 105-1 and105-2 which may be joined to one AP 130.

The BSS may include at least one STA, APs providing a distributionservice, and a distribution system (DS) 110 connecting multiple APs.

The distribution system 110 may implement an extended service set (ESS)140 extended by connecting the multiple BSSs 100 and 105. The ESS 140may be used as a term indicating one network configured by connectingone or more APs 125 or 230 through the distribution system 110. The APincluded in one ESS 140 may have the same service set identification(SSID).

A portal 120 may serve as a bridge which connects the wireless LANnetwork (IEEE 802.11) and another network (e.g., 802.X).

In the BSS illustrated in the upper part of FIG. 1, a network betweenthe APs 125 and 130 and a network between the APs 125 and 130 and theSTAs 100-1, 105-1, and 105-2 may be implemented. However, the network isconfigured even between the STAs without the APs 125 and 130 to performcommunication. A network in which the communication is performed byconfiguring the network even between the STAs without the APs 125 and130 is defined as an Ad-Hoc network or an independent basic service set(IBSS).

A lower part of FIG. 1 illustrates a conceptual view illustrating theIBSS.

Referring to the lower part of FIG. 1, the IBSS is a BSS that operatesin an Ad-Hoc mode. Since the IBSS does not include the access point(AP), a centralized management entity that performs a managementfunction at the center does not exist. That is, in the IBSS, STAs 150-1,150-2, 150-3, 155-4, and 155-5 are managed by a distributed manner. Inthe IBSS, all STAs 150-1, 150-2, 150-3, 155-4, and 155-5 may beconstituted by movable STAs and are not permitted to access the DS toconstitute a self-contained network.

The STA as a predetermined functional medium that includes a mediumaccess control (MAC) that follows a regulation of an Institute ofElectrical and Electronics Engineers (IEEE) 802.11 standard and aphysical layer interface for a radio medium may be used as a meaningincluding all of the APs and the non-AP stations (STAs).

The STA may be called various a name such as a mobile terminal, awireless device, a wireless transmit/receive unit (WTRU), user equipment(UE), a mobile station (MS), a mobile subscriber unit, or just a user.

A new frame format for implementing a next generation wireless LANsystem is required to be defined. In case a new frame format for theimplementation of a next generation wireless LAN system is defined, alegacy frame format for legacy user equipments (STAs and APs) supportingthe conventional (or legacy) wireless LAN system and the new frameformat for the next generation wireless LAN system co-exist in thewireless LAN network. The legacy user equipment cannot know about themanagement of the next generation wireless LAN and the characteristicsof the next generation wireless LAN. Therefore, a frame structure (orframe format) for the next generation wireless LAN is required to bedesigned without causing any influence on the performance of the legacyuser equipments. Similarly, a physical protocol data unit (PPDU)structure for the next generation wireless LAN is required to bedesigned without causing any influence on the performance of the legacyuser equipments.

In the related art wireless LAN system, a multi-channel allocationmethod for allocating a wider bandwidth (e.g., a bandwidth exceeding 20MHz) to one user equipment was used. In case one channel unit is said tobe equal to 20 MHz, a multi-channel may include a plurality of 20 MHzchannels. In the multi-channel allocation method, a primary channel rulewas used in order to allocate a wider bandwidth to the user equipment.In case the primary channel rule is used, limitations (or restrictions)in allocating a wider bandwidth to the user equipment exists. Morespecifically, according to the primary channel rule, in case a secondarychannel, which is adjacent to the primary channel is ‘busy’ due to itsusage in an overlapped BBS (OBBS), the STA cannot use the remainingchannels excluding the primary channel. Therefore, since the STA canonly transmit a frame through the primary channel, the STA undergoesrestrictions in transmitting a frame through a multi-channel. Therefore,since the STA can transmit frames only through the primary channel, theSTA undergoes restrictions in transmitting frames through amulti-channel. More specifically, the primary channel rule, which wasused for multi-channel allocation in the legacy wireless LAN system maycause considerable restrictions in gaining a high throughput by managinga wide (or wider) bandwidth in the current wireless LAN environment,wherein a large number of OBBSs exist.

In order to resolve such problems, a wireless LAN system supporting anorthogonal frequency division multiple access (OFDMA) technology isdisclosed in the exemplary embodiment of the present invention. In casethe OFDMA technology is used, the multi-channel may be used by not justone user equipment but by multiple user equipments simultaneouslywithout any restrictions caused by the primary channel rule. Therefore,since a wider bandwidth management is possible, the efficiency in themanagement of the wireless resources may be enhanced.

In case a maximum usage of OFDM numerology of the related art wirelessLAN system is carried out for the resource allocation that is based onthe OFDMA, it will be advantageous in that data encoding and interleaverdesigns, and so on, that were used in the related art wireless LANsystem may be re-used. However, in case an unscalable OFDM numerologymethod of the related art is used without any modification, whentransmitting data traffic by using the OFDMA based resource allocation,it may be difficult to perform transmission of diverse sizes of datatraffic and allocation of diverse sizes of resources, and, accordingly,it may be difficult to ensure scheduling flexibility.

Moreover, in case the related art OFDM numerology is used withoutmodification, the support of a diversity mode (distributed resourceallocation), which is supported in the OFDMA transmission, may alsobecome complicated, and the design of the wireless LAN system may becomemore complicated due to the diversity in the number of leftover tones(or leftover subcarriers) according to the bandwidth size.

An example of a time-frequency structure that is assumed in the wirelessLAN system according to the exemplary embodiment of the presentinvention may be as shown below.

A fast fourier transform (FFT) size/inverse fast fourier transform(IFFT) size may be defined to be equal to N times (wherein N is aninteger, e.g., N=4) of the FFT/IFFT sizes that were used in the legacywireless LAN system. For example, 256FFT/IFFT may be applied for abandwidth of 20 MHz, 512FFT/IFFT may be applied for a bandwidth of 40MHz, 1024FFT/IFFT may be applied for a bandwidth of 80 MHz, or2048FFT/IFFT may be applied for a consecutive bandwidth of 160 MHz or anon-consecutive bandwidth of 160 MHz.

Subcarrier spacing may be equal to 1/N times (wherein N is an integer,e.g., 78.125 kHz when N=4) of the subcarrier spacing that was used inthe legacy wireless LAN system.

An inverse discrete fourier transform (IDFT)/discrete fourier transform(DFT) length (or valid symbol length) that is based on IDFT/DFT (orFFT/IFFT) may be equal to N times the IDFT/DFT length used in the legacywireless LAN system. For example, in case the IDFT/DFT length is equalto 3.2 μs and N=4 in the legacy wireless LAN system, the IDFT/DFT lengthin the wireless LAN system according to the exemplary embodiment of thepresent invention may be equal to 3.2 μs*4(=12.8 μs).

The length of an OFDM symbol may correspond to a value wherein a guardinterval (GI) length is added to an IDFT/DFT length. The length of a GImay be equal to diverse values, such as 0.4 μs, 0.8 μs, 1.6 μs, 2.4 μs,and 3.2 μs.

In case of using the OFDMA based resource allocation method according tothe exemplary embodiment of the present invention, different sizes ofresource allocation units may be used. More specifically, a regularresource unit (RRU) and an irregular resource unit (IRU) may be definedfor the resource allocation based on OFDMA.

An AP may determine a downlink transmission resource and/or uplinktransmission resource for at least one STA based on the plurality ofresource units. The AP may transmit at least one PPDU to at least oneSTA through the downlink transmission resource. Moreover, the AP mayreceive at least one PPDU being transmitted by at least one STA throughthe uplink transmission resource.

The RRU may correspond to the resource unit having the relatively largersize (larger size resource unit) as compared to the IRU. The RRU may bedefined based on the size of the bandwidth that was supported in thelegacy wireless LAN system. For example, the RRU may be defined to havethe sizes of 26 tones, 56 tones, 114 tones, and 242 tones. The RRU maybe defined to have the same size regardless of the size of the bandwidththat is available for usage (e.g., 20 MHz, 40 MHz, 80 MHz, 160 MHz,etc.), or the RRU may be defined to have a size that is subordinate tothe size of the bandwidth that is available for usage. For example, withan increase in the size of the bandwidth that is available for usage,the size of the RRU may also be defined to have a relatively largersize. A tone may be interpreted to have the same meaning as asubcarrier.

The IRU may correspond to the resource unit having the relativelysmaller size (smaller size resource unit) as compared to the RRU.

As another term, the RRU may be expressed as a basic tone unit (BTU),and the IRU may be expressed as a small tone unit (STU).

Resource units, such as the RRU and the IRU, may be allocated within theentire bandwidth by considering a left guard tone and a right guardtone, which are respectively allocated at each end of the entirebandwidth for interference alleviation, and a direct current (DC) tone,which is located at the center of the entire bandwidth. The number ofleft guard tones, right guard tones, and DC tones may each correspond toa number that is not subordinate to the total size of the entirebandwidth and may each correspond to a fixed number regardless of thesize of the entire bandwidth. For example, the number of left guardtones/right guard tones may be equal to 6/5 or 7/6, and the number of DCtones may be equal to 5 or 3.

The allocation method (allocation number, allocation location, etc.) ofresource units, such as the RRU and the IRU, may be configured byconsidering resource application efficiency, scalability (orextendibility) according to the entire bandwidth. The allocation methodof the resource units, such as the RRU and the IRU, may be defined inadvance or may be signaled based on diverse methods (e.g., signalingbased on a signal field that is included in a PPDU header of a PPDU).

For example, for a systematic allocation of resource units within theentire bandwidth, the sum of the number of tones allocated to the RRUand the number of tones allocated to the IRU is essentially set to be adivisor of 256 (e.g., 128, 64, 32, etc.), and then, the RRU and the IRU,which are connected to be consecutive to one another, may beconsecutively repeated within the entire bandwidth. Additionally, thesum of the number of left guard tones, right guard tones, and DC tonesmay be set to be equal to the number of tones corresponding to at leastone IRU (e.g., the number of tones corresponding to 2 IRUs).

In case the resource allocation is carried out based on theabove-described method, the resource allocation may be performed in aformat, such as left guard tone/RRU/IRU/RRU/IRU/ . . . /RRU/DCtone/RRU/IRU . . . /RRU/right guard tone. In case the resourceallocation is performed as described above, the number of RRUs beingallocated within the entire bandwidth may be 2 times larger than thenumber of IRUs being allocated within the entire bandwidth.

In case the number of tones allocated to the IRU is small, a plurality(e.g., 2) physical IRUs may be grouped (or bundled) so as to be definedas a logical IRU, which may be used as a minimum unit for resourceallocation. For example, two IRUs that are adjacent to one anotherwithin the entire bandwidth may be defined as one logical IRU. In orderto configure two physical IRUs that are adjacent to one another as onelogical IRU, by changing the positions of the IRU and the RRU in thestructure shown below in FIG. 2, a new format of left guardtone/RRU/IRU/RRU/RRU/IRU/RRU . . . , i.e., a structure whereinRRU/IRU/RRU is repeated may be configured. In case the positions of theIRUs and the RRUs are changed near the DC tone, two IRUs may be adjacentto one another near the DC tone, and the two adjacent IRUs located nearthe DC tone may be collectively defined as one logical IRU.

Additionally, according to the exemplary embodiment of the presentinvention, in case the uplink transmission from the STA to the AP iscarried out, a resource unit having a small size, such as the IRU maynot be allocated as the uplink resource in order to alleviate theinterference between the users. Moreover, in accordance with the changein the number of tones being allocated to each of the left guard tones,the right guard tones, and the DC tones, at least one or more IRUs maynot be allocated in the above-described resource allocation method.

Additionally, according to the exemplary embodiment of the presentinvention, the above-described methods may be combined by hybridcombination so as to carry out resource allocation.

Moreover, according to the exemplary embodiment of the presentinvention, one RRU may be logically divided into a plurality of smallRRUs (or sub-RRUs) so as to gain a diversity effect. For example, oneRRU being allocated to 242 tones may be divided into 2 sub-RRUs eachbeing allocated to 121 tones or 22 sub-RRUs each being allocated to 11tones. One RRU being allocated to 114 tones may be divided into 2sub-RRUs each being allocated to 57 tones or 6 sub-RRUs each beingallocated to 9 tones. One RRU being allocated to 56 tones may be dividedinto 2 sub-RRUs each being allocated to 28 tones or 4 sub-RRUs eachbeing allocated to14 tones. One RRU being allocated to 26 tones may bedivided into 2 sub-RRUs each being allocated to 13.

Each of the plurality of sub-RRUs being included in one RRU, which isdescribed above, may be allocated to a plurality of STAs. For example,each of the plurality of sub-RRUs being included in each of theplurality of RRUs may be allocated as resource for one STA. In otherwords, the resource for one STA may cover a plurality of RRUs. Morespecifically, for example, in case 26 tones are allocated for one STA, 2sub-RRUs each being allocated to 13 tones and each being included in 2RRUs that are allocated to the 26 tones may be allocated as resource forone STA. In case the above-described resource allocation method is used,the diversity effect may be gained.

Furthermore, according to the exemplary embodiment of the presentinvention, in case of a pilot subcarrier (or pilot tone or pilot) withinan IRU, in case one pilot subcarrier is allocated to the IRU, the pilotsubcarrier may be allocated to a subcarrier that is located at thecenter of the IRU, and, in case two pilot subcarriers are allocated tothe IRU, each of the 2 pilot subcarriers may be respectively allocatedto subcarriers located between each end of the IRU and the subcarrierlocated at the center of the IRU.

FIG. 2 is a conceptual view illustrating a resource allocation methodaccording to an exemplary embodiment of the present invention.

FIG. 2 discloses a resource allocation according to the size of theentire bandwidth, in a case when the number of tones being allocated tothe RRU (or also referred to as a basic resource unit (BRU)) is equal to56 and when the number of tones being allocated to the IRU is equal to8. In case 56 tones are allocated to the RRU, the same basic OFDMnumerology that is used in 20 MHz in the legacy wireless LAN system maybe used. Therefore, an interleaver (or data tone interleaver) that wasused in the legacy wireless LAN system may be re-used.

Additionally, the sum of the number of tones allocated to the RRU(hereinafter, a RRU size may also be used in the same meaning) and thenumber of tones allocated to the IRU (hereinafter, an IRU size may alsobe used in the same meaning) is equal to 64, which is a divisor of 256.Therefore, a systematic design may be easily configured.

Resource allocation for 20 MHz is disclosed on the left side of FIG. 2,resource allocation for 40 MHz is disclosed at the center of FIG. 2, andresource allocation for 80 MHz is disclosed on the right side of FIG. 2.Resource allocation for 160 MHz may correspond to a structure where inthe resource allocation for 80 MHz is repeated. Each of the RRU and theIRU, which correspond to two resource units, may be allocated to eachindependent STA. Alternatively, depending upon the system environment,two resource units (RRU, IRU) may be simultaneously allocated to oneSTA.

In case the RRU size is equal to 56 tones and the IRU size is equal to 8tones, the number of RRU allocations, the number of IRU allocations, andthe number of DC tones and guard tones for each bandwidth size may be asshown below in Table 1. Table 1 discloses the numerology for eachbandwidth size.

TABLE 1 Number of DC tones and Number number of guard tones BW Number ofRRUs of IRUs (guard subcarriers) 20 MHz 4 (224 tones) 2 (16 tones) 16(DC: 5, GS: 11 or DC: 3, GS: 13) 40 MHz 8 (448 tones) 6 (48 tones) 16(DC: 5, GS: 11 or DC: 3, GS: 13) 80 MHz 16 (896 tones)  14 (112 tones)16 (DC: 5, GS: 11 or DC: 3, GS: 13)

Referring to Table 1, in the 20 MHz bandwidth, 4 RRUs and 2 IRUs may beallocated, and, in the 40 MHz bandwidth, 8 RRUs and 6 IRUs may beallocated, and, in the 80 MHz bandwidth, 16 RRUs and 14 IRUs may beallocated.

More specifically, in the 20 MHz bandwidth, resource allocation may beperformed in a structure (or format) of left guard tone/RRU/IRU/RRU/DCtone/RRU/IRU/RRU/right guard tone. Similarly, in the 40 MHz bandwidthand the 80 MHz bandwidth, resource allocation may be performed in thestructure of left guard tone/RRU/IRU/RRU/IRU/RRU/ . . . /IRU/RRU/DCtone/RRU/IRU/ . . . /RRU/IRU/RRU/IRU/RRU/right guard tone. RRUs may berespectively allocated at locations adjacent to the left guard tone andthe right guard tone, and, thereafter, IRU/RRU may be repeatedlyallocated toward the direction of the DC tone from each guard tone, and,herein, resource allocation may be performed so that RRUs are adjacentto the DC tone. As described above, by changing the allocated positionsof the RRU and the IRU near the DC tone, so that the IRU can be locatednear the DC tone, as described above, the resource allocation may alsobe performed in the structure of / . . . /RRU/RRU/IRU/DCtone/IRU/RRU/RRU/ . . . /.

Resource allocation for the 160 MHz bandwidth may be performed based ona repetition of the resource allocation for the 80 MHz bandwidth.Therefore, 32 RRUs and 28 IRUs may be allocated in the 160 MHzbandwidth.

Additionally, referring to Table 1, the sum of the number of DC tonesand the number of guard tones (the sum of the number of left guard tonesand the number of right guard tones) may be equal to a fixed value(e.g., 16) regardless of the bandwidth. The sum of the number of DCtones and the number of guard tones may be equal to a multiple of theIRU size.

As described above, although individual IRU units may be allocated tothe STA, two physical IRUs may be bundled (or grouped) so as to beallocated as wireless resource for the STA in a logical IRU unit. Asshown in FIG. 2, in case the IRU size is equal to 8 tones, the size ofthe logical tone may be equal to 16 tones, and 16 tones may be used as aminimum resource allocation unit. Hereinafter, in the exemplaryembodiment of the present invention, a resource allocation unit that isconfigured by grouping n (wherein n is an integer) number of physicalIRUs may be expressed by the term logical nIRU. The locations of theplurality of IRUs configuring the logical nIRU may be adjacent orconsecutive to one another or may be allocated without consideringwhether or not the IRUs are adjacent to one another. The logical nIRUmay correspond to a minimum resource allocation unit. For example, theresource allocation unit that is configured by grouping two physicalIRUs may be expressed by the term logical 2IRU.

According to the exemplary embodiment of the present invention, the IRUsize may vary. Hereinafter, in case the RRU size is equal to 56 tones,the IRU size is equal to 13 tones or 9 tones instead of 8 tones, thefollowing resource allocation is disclosed.

Table 2 shown below discloses the resource allocation corresponding tothe 80 MHz bandwidth, in case the RRU size is equal to 56 tones and theIRU size is equal to 13 tones.

TABLE 2 Number of Number of Total number tones units of tones RRU 56 15840 IRU 13 13 169 Left guard tone 6 Right guard tone 5 DC 4 1024

Table 3 shown below discloses the resource allocation corresponding tothe 40 MHz bandwidth, in case the RRU size is equal to 56 tones and theIRU size is equal to 13 tones.

TABLE 3 Number of Number of Total number tones units of tones RRU 56 7392 IRU 13 8 104 left guard 6 right guard 5 DC 5 512

Table 4 shown below discloses the resource allocation corresponding tothe 20 MHz bandwidth, in case the RRU size is equal to 56 tones and theIRU size is equal to 13 tones.

TABLE 4 Number of Number of Total number tones units of tones RRU 56 4224 IRU 13 1 13 left guard 6 right guard 5 DC 8 256

Table 5 shown below discloses the resource allocation corresponding tothe 20 MHz/40 MHz/80 MHz bandwidths, in case the RRU size is equal to 56tones and the IRU size is equal to 9 tones.

TABLE 5 Sum of the number of DC tones and the BW Number of RRUs Numberof IRUs number of GS tones 20 MHz 4 (224 tones) 2 (18 tones) 14 (DC: 3,GS: 11) 40 MHz 8 (448 tones) 5 (45 tones) 19 (DC: 8, GS: 11 or DC: 3,GS: 16) 80 MHz 16 (896 tones)  12 (108 tones) 20 (DC: 3, GS: 17 or DC:9, GS: 11)

Additionally, according to the exemplary embodiment of the presentinvention, the RRU size may also vary. Hereinafter, in case the RRU sizeis equal to 26 tones, the IRU size is equal to 8 tones, the followingresource allocation is disclosed. A number of RRUs and a number of IRUsthat are larger than the case when the RRU size is equal to 56 tones maybe allocated to the entire bandwidth. Also, in case the RRU size isequal to 26 tones, resource allocation may be supported at a moreaccurate granularity as compared to the case when the RRU size is equalto 52 tones.

Table 6 shown below discloses the resource allocation corresponding tothe 20 MHz/40 MHz/80 MHz bandwidths, in case the RRU size is equal to 26tones and the IRU size is equal to 13 tones.

TABLE 6 Sum of the number of DC tones and the number BW Number of RRUsNumber of IRUs of GS tones 20 MHz  8 (208 tones) 4 (32 tones) 16 (DC: 5,GS: 11 or DC: 3, GS: 13) 40 MHz 16 (416 tones) 10 (80 tones)  16 (DC: 5,GS: 11 or DC: 3, GS: 13) 80 MHz 32 (832 tones) 22 (176 tones) 16 (DC: 5,GS: 11 or DC: 3, GS: 13)

Table 7 shown below discloses the resource allocation corresponding tothe 80 MHz bandwidth, in case the RRU size is equal to 26 tones and theIRU size is equal to 6 tones.

TABLE 7 Number of Number of Total number tones units of tones RRU 26 32832 IRU 6 30 180 left guard 5 right guard 4 DC 3 1024

Table 8 shown below discloses the resource allocation corresponding tothe 40 MHz bandwidth, in case the RRU size is equal to 26 tones and theIRU size is equal to 6 tones.

TABLE 8 Number of Number of Total number tones units of tones RRU 26 16416 IRU 6 14 84 left guard 5 right guard 4 DC 3 512

Table 9 shown below discloses the resource allocation corresponding tothe 20 MHz bandwidth, in case the RRU size is equal to 26 tones and theIRU size is equal to 6 tones.

TABLE 9 Number of Number of Total number tones units of tones RRU 26 8208 IRU 6 6 36 left guard 5 right guard 4 DC 3 256

Moreover, according to the exemplary embodiment of the presentinvention, the RRU size may be equal to 114 tones and the IRU size maybe equal to 7 tones. Table 10 to Table 12 shown below respectivelydisclose resource allocations corresponding to a case when the RRU sizeis equal to 114 tones and the IRU size is equal to 7 tones.

Table 10 shown below discloses the resource allocation corresponding tothe 80 MHz bandwidth, in case the RRU size is equal to 114 tones and theIRU size is equal to 7 tones.

TABLE 10 Number of Number of Total number tones units of tones RRU 114 8912 IRU 7 14 98 left guard 6 right guard 5 DC 3 1024

Table 11 shown below discloses the resource allocation corresponding tothe 40 MHz bandwidth, in case the RRU size is equal to 114 tones and theIRU size is equal to 7 tones.

TABLE 11 Number of Number of Total number tones units of tones RRU 114 4456 IRU 7 6 42 left guard 6 right guard 5 DC 3 512

Table 12 shown below discloses the resource allocation corresponding tothe 20 MHz bandwidth, in case the RRU size is equal to 114 tones and theIRU size is equal to 7 tones.

TABLE 12 Number of Number of Total number tones units of tones RRU 114 2228 IRU 7 2 14 left guard 6 right guard 5 DC 3 256

In case the RRU size is equal to 114 tones and the IRU size is equal to7 tones, the resource allocation corresponding to the 80 MHz/40 MHz/20MHz bandwidths may be performed as shown below.

80 MHz: Left guard(6)/RRU(114)/logical 2IRU(14)/RRU(114)/logical2IRU(14)/RRU(114)/logical2IRU(14)/RRU(114)/IRU(7)/DC(3)/IRU(7)/RRU(114)/logical2IRU(14)/RRU(114)/logical 2IRU(14)/RRU(114)/logical2IRU(14)/RRU(114)/right guard (5)

40 MHz: Left guard(6)/RRU(114)/logical2IRU(14)/RRU(114)/IRU(7)/DC(3)/IRU(7)/RRU(114)/logical2IRU(14)/RRU(114)/right guard (5)

20 MHz: Left guard(6)/RRU(114)/IRU(7)/DC(3)/IRU(7)/RRU(114)/right guard(5)

In the above-described 20 MHz/40 MHz/80 MHz allocation, the positions ofeach of the RRUs, IRUs, and logical 2IRUs may vary within the entirebandwidth.

Alternatively, considering the diversity, the resource allocation ineach of 80 MHz/40 MHz/20 MHz may be performed as described below.

80 MHz: Left guard(6)/IRU(7)/RRU(114)/logical2IRU(14)/RRU(114)/IRU(7)/RRU(114)/logical2IRU(14)/RRU(114)/IRU(7)/DC(3)/IRU(7)/RRU(114)/logical2IRU(14)/RRU(114)/IRU(7)/RRU(114)/logical 2IRU(14)/RRU(114)/IRU(7)/rightguard (5)

40 MHz: Leftguard(6)/IRU(7)/RRU(114)/IRU(7)/RRU(114)/IRU(7)/DC(3)/IRU(7)/RRU(114)/IRU(7)/RRU(114)/IRU(7)/rightguard (5)

20 MHz: Left guard(6)/IRU(7)/RRU(114)/DC(3)/RRU(114)/IRU(7)/right guard(5)

The above-described resource allocation is merely exemplary, and,therefore, resource allocation that is based on the RRU/IRU within theentire bandwidth may also be performed by using diverse methods otherthan the above-described resource allocation.

FIG. 3 is a conceptual view illustrating a resource allocation methodaccording to an exemplary embodiment of the present invention.

FIG. 3 discloses a method of varying the RRU size in accordance with thesize of the entire bandwidth.

Referring to FIG. 3, in case the size of the entire bandwidth is equalto 20 MHz, the RRU size may be equal to 26 tones, and, in case the sizeof the entire bandwidth is equal to 40 MHz, the RRU size may be equal to56 tones, and, in case the size of the entire bandwidth is equal to 80MHz, the RRU size may be equal to 26 tones.

The IRU size may be defined to be equal to a fixed value (e.g., 7 tones)that remains unchanged in accordance with the entire bandwidth, and 14tones corresponding to the logical 2IRU may be used as the minimumresource allocation unit. The logical 2IRU corresponding to 14 tones mayinclude two pilot subcarriers (or pilot tones). Among the 14 tonescorresponding to the minimum resource allocation unit, 12 tonesexcluding the 2 pilot subcarriers may be used as data tones. The 12 datatones may facilitate the support of diverse modulation and coding scheme(MCS) decoding. Most particularly, in 80 MHz, the sum of the RRU sizeand the minimum allocation unit (two IRUs) corresponds to RRU+2IRU=114tones+14 tones=128 tones, which corresponds to a divisor of 256.

The left side of FIG. 3 discloses RRU/IRU allocated to 80 MHz.

Referring to the left side of FIG. 3, left guard tone/RRU(114)/logical2IRU(14)/RRU(114)/logical 2IRU(14)/RRU(114)/logical2IRU(14)/RRU(114)/IRU(7)/DC/IRU(7)/RRU(114)/logical2IRU(14)/RRU(114)/logical 2IRU(14)/RRU(114)/logical2IRU(14)/RRU(114)/right guard tone may be allocated within the entirebandwidth.

The center of FIG. 3 discloses RRU/IRU allocated to 40 MHz.

Referring to the center of FIG. 3, left guardtone/RRU(56)/RRU(56)/logical2IRU(14)/RRU(56)/RRU(56)/IRU(7)/DC/IRU(7)/RRU(56)/RRU(56)/logical2IRU(14)/RRU(56)/RRU(56)/right guard tone may be allocated within theentire bandwidth.

The right side of FIG. 3 discloses RRU/IRU allocated to 20 MHz.

Referring to the right side of FIG. 3, left guardtone/RRU(26)/RRU(26)/IRU(7)/RRU(26)/RRU(26)/IRU(7)/DC/IRU(7)/RRU(26)/RRU(26)/IRU(7)/RRU(26)/RRU(26)/rightguard tone may be allocated within the entire bandwidth.

In FIG. 3, the disclosed positions corresponding to each of the RRUs,IRUs, and logical 2IRU within the entire bandwidth correspond toexemplary positions. Each of the RRUs, IRUs, and logical 2IRU may bediversely allocated within the entire bandwidth.

FIG. 4 is a conceptual view illustrating a resource allocation methodaccording to an exemplary embodiment of the present invention.

For example, in order to re-use the legacy OFDM numerology, in 80 MHz,the minimum granularity may be set to 10 MHz (114 tones), and, in 40MHz, the minimum granularity may be set to 5 MHz (56 tones), and, in 20MHz, the minimum granularity may be set to 2.5 MHz (26 tones).

Alternatively, since the 80 MHz bandwidth is a dominant bandwidth of thesystem, the 80 MHz bandwidth is optimized to one resource granularity,and the remaining bandwidths may be designed to inclusively support onegranularity.

Hereinafter, in case the minimum granularity in 80 MHz is equal to 10MHz and the minimum granularity in each of 40 MHz and 20 MHz isrespectively equal to 5 MHz, Table 13 to Table 15 respectively discloseresource allocations in each of 80 MHz, 40 MHz, and 20 MHz bandwidths.

Table 13 shown below discloses a case when the minimum granularity isequal to 10 MHz in the 80 MHz bandwidth.

TABLE 13 Number of Number of Total number tones units of tones RRU 114 8912 IRU 7 14 98 left guard 6 right guard 5 DC 3 1024

Table 14 shown below discloses a case when the minimum granularity isequal to 5 MHz in the 40 MHz bandwidth.

TABLE 14 Number of Number of Total number tones units of tones RRU 56 8448 IRU 7 6 42 left guard 6 right guard 5 DC 11 512

Table 15 shown below discloses a case when the minimum granularity isequal to 5 MHz in the 20 MHz bandwidth.

TABLE 15 Number of Number of Total number tones units of tones RRU 56 4224 IRU 7 2 14 left guard 6 right guard 5 DC 7 256

Referring to Table 13 to Table 15, a unit of the basic resourceallocation granularity and a RRU size may be identical.

More specifically, in a bandwidth of 80 MHz, the minimum granularity (orbasic resource allocation granularity) may be equal to 10 MHz (114tones), one RRU size may be equal to 114 tones, and one IRU size may beequal to 7 tones. At this point, 8 RRUs and 14 IRUs may be allocated tothe bandwidth. A logical 2IRU may be used as the minimum allocationunit. Additionally, the number of left guard tones may be equal to 6,the number of right guard tones may be equal to 5, and the number of DCtones may be equal to 3.

Additionally, in a bandwidth of 40 MHz, the minimum granularity may beequal to 5 MHz (56 tones), one RRU size may be equal to 56 tones, andone IRU size may be equal to 7 tones. At this point, 8 RRUs and 6 IRUsmay be allocated to the bandwidth. A logical 2IRU may be used as theminimum allocation unit. Additionally, the number of left guard tonesmay be equal to 6, the number of right guard tones may be equal to 5,and the number of DC tones may be equal to 11.

Additionally, in a bandwidth of 20 MHz, the minimum granularity may beequal to 5 MHz (56 tones), one RRU size may be equal to 56 tones, andone IRU size may be equal to 7 tones. At this point, 4 RRUs and 2 IRUsmay be allocated to the bandwidth. A logical 2IRU may be used as theminimum allocation unit. Additionally, the number of left guard tonesmay be equal to 6, the number of right guard tones may be equal to 5,and the number of DC tones may be equal to 7.

The left side of FIG. 4 discloses RRU/IRU allocated to 80 MHz.

Referring to the left side of FIG. 4, left guard tone/RRU(114)/logical2IRU(14)/RRU(114)/logical 2IRU(14)/RRU(114)/logical2IRU(14)/RRU(114)/IRU(7)/DC/IRU(7)/RRU(114)/logical2IRU(14)/RRU(114)/logical 2IRU(14)/RRU(114)/logical2IRU(14)/RRU(114)/right guard tone may be allocated within the entirebandwidth.

The center of FIG. 4 discloses RRU/IRU allocated to 40 MHz.

Referring to the center of FIG. 4, left guardtone/RRU(56)/RRU(56)/logical2IRU(14)/RRU(56)/RRU(56)/IRU(7)/DC/IRU(7)/RRU(56)/logical2IRU(14)/RRU(56)/RRU(56)/RRU(56)/right guard tone may be allocatedwithin the entire bandwidth.

The right side of FIG. 4 discloses RRU/IRU allocated to 20 MHz.

Referring to the right side of FIG. 4, left guardtone/RRU(56)/RRU(56)/IRU(7)/DC/IRU(7)/RRU(56)/RRU(56)/right guard tonemay be allocated within the entire bandwidth.

In FIG. 4, the disclosed allocation positions of the RRUs and theallocation positions of the IRUs correspond to exemplary positions. Eachof the IRUs may be diversely allocated to physically separatedsubcarriers (or tones) and may be used as one resource allocation unit.

Alternatively, according to the exemplary embodiment of the presentinvention, the minimum granularity in 80 MHz may be set to 5 MHz (56tones), the minimum granularity in 40 MHz may be set to 2.5 MHz (26tones), and the minimum granularity in 20 MHz may be set to 2.5 MHz (26tones).

Table 16, Table 17, and Table 18 shown below respectively representresource allocations of RRUs and a logical 2IRU unit corresponding to 80MHz, 40 MHz, and 20 MHz. In Table 16 to Table 18 shown below, althoughthe IRU being allocated to 14 tones may indicate the logical 2IRU, theIRU may also indicate one physical IRU.

TABLE 16 Number of Number of Total number tones units of tones RRU 114 8912 IRU 14 7 98 left guard 6 right guard 5 DC 3 1024

Referring to Table 16, 8 114-tone RRUs and 7 logical 2IRUs may beallocated to the 80 MHz bandwidth.

TABLE 17 Number of tones Number of units Total number of tones RRU 56 8448 IRU 14 3 42 left guard 6 right 5 guard DC 11 512

Referring to Table 17, 8 56-tone RRUs and 3 logical 2IRUs may beallocated to the 40 MHz bandwidth.

TABLE 18 Number of tones Number of units Total number of tones RRU 26 8208 IRU 14 2 28 left guard 6 right 5 guard DC 9 256

Referring to Table 18, 8 26-tone RRUs and 2 logical 2IRUs may beallocated to the 20 MHz bandwidth.

Table 19, Table 20, and Table 21 shown below represent combinations ofother additional RRUs and IRUs within the 20 MHz bandwidth. In Table 19ad Table 20 shown below, although the IRU being allocated to 14 tonesmay indicate the logical 2IRU, the IRU may also indicate one physicalIRU.

TABLE 19 Number of tones Number of units Total number of tones RRU 26 4104 IRU 14 10 140 left guard 6 right 5 guard DC 1 256

TABLE 20 Number of tones Number of units Total number of tones RRU 26 6156 IRU 14 6 84 left guard 6 right 5 guard DC 5 256

TABLE 21 Number of tones Number of units Total number of tones RRU 56 2112 IRU 8 16 128 left guard 6 right 5 guard DC 5 256

Table 22 shown below discloses resource allocation within the 20 MHzbandwidth that is based on RRUs being allocated to 56 tones and IRUsbeing allocated to 13 tones. The logical 2IRU corresponding to 26 tonesmay be used as the minimum resource allocation unit.

TABLE 22 Number of tones Number of units Total number of tones RRU 56 2112 IRU 13 10 130 left guard 6 right 5 guard DC 3 256

Table 23 shown below discloses resource allocation within the 40 MHzbandwidth that is based on RRUs being allocated to 28 tones and IRUsbeing allocated to 13 tones. The logical 2IRU corresponding to 26 tonesmay be used as the minimum resource allocation unit.

TABLE 23 Number of tones Number of units Total number of tones RRU 28 14392 IRU 13 8 104 left guard 6 right 5 guard DC 5 512

Table 24 shown below discloses resource allocation within the 80 MHzbandwidth that is based on RRUs being allocated to 56 tones and IRUsbeing allocated to 13 tones. The logical 2IRU corresponding to 26 tonesmay be used as the minimum resource allocation unit.

TABLE 24 Number of tones Number of units Total number of tones RRU 56 10560 IRU 13 34 442 left guard 6 right 5 guard DC 11 1024

Table 25 shown below discloses resource allocation within the 80 MHzbandwidth that is based on RRUs being allocated to 57 tones and IRUsbeing allocated to 26 tones.

TABLE 25 Number of tones Number of units Total number of tones RRU 57 14798 IRU 26 8 208 left guard 6 right 5 guard DC 7 1024

Additionally, according to the exemplary embodiment of the presentinvention, each of the RRUs and the IRUs may be respectively allocatedas shown below in each of 20 MHz, 40 MHz, and 80 MHz. {RRU, IRU}={56tones, 7 tones} may be allocated for the 20 MHz bandwidth, {RRU,IRU}={56 tones, 7 tones} (or ={114 tones, 7 tones} may be allocated forthe 40 MHz bandwidth, and {RRU, IRU}={114 tones, 7 tones} may beallocated for the 80 MHz bandwidth.

FIG. 5 is a conceptual view illustrating a resource allocation accordingto an exemplary embodiment of the present invention.

FIG. 5 discloses a resource allocation of {RRU, IRU}={56 tones, 7 tones}for the 20 MHz bandwidth, which is shown below in Table 26.

TABLE 26 Number of tones Number of units Total number of tones RRU 56 4224 IRU 7 2 14 left guard 6 right 5 guard DC 7 256

Referring to the left side of FIG. 5, left guardtone/IRU(7)/RRU(56)/RRU(56)/DC tone/RRU(56)/RRU(56)/IRU(7)/right guardtone may be allocated within the 20 MHz bandwidth.

Referring to the right side of FIG. 5, left guardtone/RRU(56)/IRU(7)/RRU(56)/DC tone/RRU(56)/RRU(7)/RRU(56)/right guardtone may be allocated within the 20 MHz bandwidth.

The above-described allocation of the RRUs and the IRUs may vary inaccordance with the number of users (or STAs). In the followingdescription, in case the number of users is equal to 1, 2, 3, 4, and 5,examples of allocating resources to each number of users will bedisclosed. The allocation order may be varied, and it will beessentially assumed that all resources are allocated to the user(s)within the entire bandwidth.

One (1) user (In case the number of allocation is equal to 1): thenumerology of 256 FFT (242 tones) that is used in the legacy 80 MHzbandwidth may be applied and used in 20 MHz. 8 pilot tones may beincluded. More specifically, 242 tones may be allocated for one user.

Two (2) users (In case the number of allocation is equal to 2): 4 RRUs(2RRU+2RRU) may be allocated to user1, and 2 IRUs (2IRU) may beallocated to user2. The 4 RRUs may have a structure of 2 2RRUs eachbeing configured of 2 RRUs. A 2RRU may be allocated to 112 tones,wherein the 112 tones include 108 data tones and 4 pilot tones. A 2IRUmay be allocated to 14 tones, wherein the 14 tones include 12 data tonesand 2 pilot tones. In case the entire bandwidth is allocated to twousers, in order to transmit data to user1, 2-block data interleavingusing a legacy interleaver having the size of 108 may be performed.

Three (3) users (In case the number of allocation is equal to 3): a 2RRUmay be allocated to user1, another 2RRU may be allocated to user2, and a2IRU may be allocated to user3. A 2RRU may be allocated to 112 tones,wherein the 112 tones include 108 data tones and 4 pilot tones. A 2IRUmay be allocated to 14 tones, wherein the 14 tones include 12 data tonesand 2 pilot tones. In order to transmit data to each of user1 and user2,block data interleaving using a legacy interleaver having the size of108 may be performed.

Four (4) users (In case the number of allocation is equal to 4): a RRUmay be allocated to user1, another RRU may be allocated to user2, a 2RRUmay be allocated to user3, and a 2IRU may be allocated to user4. A 2RRUmay be allocated to 112 tones, wherein the 112 tones include 108 datatones and 4 pilot tones. A RRU may be allocated to 56 tones, wherein the56 tones include 52 data tones and 4 pilot tones. A 2IRU may beallocated to 14 tones, wherein the 14 tones include 12 data tones and 2pilot tones. In order to transmit data to each of user1 and user2, blockdata interleaving using a legacy interleaver having the size of 52 maybe performed, and, in order to transmit data to user3, block datainterleaving using a legacy interleaver having the size of 108 may beperformed.

Five (5) users (In case the number of allocation is equal to 5): a RRUmay be allocated to user1, a RRU may be allocated to user2, a RRU may beallocated to user3, a RRU may be allocated to user4, and a 2IRU may beallocated to user5. A RRU may be allocated to 56 tones, wherein the 56tones include 52 data tones and 4 pilot tones. A 2IRU may be allocatedto 14 tones, wherein the 14 tones include 12 data tones and 2 pilottones. In order to transmit data to each of user1 to user4, block datainterleaving using a legacy interleaver having the size of 52 may beperformed.

More specifically, in case the number of users is equal to 1-5, thelegacy interleaver (data interleaver) may be used for each user.

The above-described allocation of RRU/IRU in accordance with the numberof users within the 20 MHz bandwidth is merely exemplary, and,therefore, the RRU/IRU may be allocated by using diverse methods, andsuch exemplary embodiments are also included in the scope of the presentinvention.

FIG. 6 is a conceptual view illustrating a resource allocation accordingto an exemplary embodiment of the present invention.

FIG. 6 discloses a resource allocation of {RRU, IRU}={56 tones, 7 tones}for the 40 MHz bandwidth, which is shown below in Table 27.

TABLE 27 Number of tones Number of units Total number of tones RRU 56 8448 IRU 7 6 42 left guard 6 right 5 guard DC 11 512

Referring to FIG. 6, left guardtone/RRU(56)/IRU(7)/RRU(56)/IRU(7)/RRU(56)/IRU(7)/RRU(56)/DCtone/RRU(56)/IRU(7)/RRU(56)/IRU(7)/RRU(56)/IRU(7)/RRU(56)/right guardtone may be allocated within the 40 MHz bandwidth.

The above-described allocation of the RRUs and the IRUs may vary inaccordance with the number of users. In the following description, incase the number of users is equal to 1, 2, 3, 4, and 5, examples ofallocating resources to each number of users will be disclosed. Theallocation order may be varied, and it will be essentially assumed thatall resources are allocated to the user(s) within the entire bandwidth.

One (1) user: the numerology of 256 FFT (242 tones) that is used in thelegacy 80 MHz bandwidth may be applied and used in 40 MHz. 8 pilot tonesmay be included. Alternatively, 490 tones configured of a combination of8 RRUs (8RRU)+6 IRUs (6IRU) may be allocated to the user.

Two (2) users: 8 RRUs (8RRU) may be allocated to user1, and 6 IRUs(6IRU) may be allocated to user2. Each RRU may be allocated to 56 tones,wherein the 56 tones include 52 data tones and 4 pilot tones. Therefore,a 8RRU may be allocated to 416(52*8) tones as the data tones and may beallocated to 32(4*8) tones as the pilot tones. Accordingly, each IRU maybe allocated to 7 tones, wherein the 7 tones include 6 data tones and 1pilot tone. Therefore, a 6IRU may be allocated to 36(6*6) tones as thedata tones and may be allocated to 6(1*6) tones as the pilot tones.

Three (3) users: a 4RRU may be allocated to user1, a 4RRU may beallocated to user2, and a 6IRU may be allocated to user3. Alternatively,a 6RRU may be allocated to user1, a 2RRU may be allocated to user2, anda 6IRU may be allocated to user3. Each RRU may be allocated to 56 tones,wherein the 56 tones include 52 data tones and 4 pilot tones. Each IRUmay be allocated to 7 tones, wherein the 7 tones include 6 data tonesand 1 pilot tone. Alternatively, the IRU may be segmented to smallersegments and then be allocated to each user.

Four (4) users˜seven(7) users: since the RRU size is equal to 56 tones,this structure may easily support the legacy interleaver size.Therefore, the RRUs and the IRUs may be allocated to each of theplurality of users by using diverse combinations.

The above-described allocation of RRU/IRU in accordance with the numberof users within the 40 MHz bandwidth is merely exemplary, and,therefore, the RRU/IRU may be allocated by using diverse methods, andsuch exemplary embodiments are also included in the scope of the presentinvention.

FIG. 7 is a conceptual view illustrating a resource allocation accordingto an exemplary embodiment of the present invention.

FIG. 7 discloses a resource allocation of {RRU, IRU}={114 tones, 7tones} for the 40 MHz bandwidth, which is shown below in Table 28.

TABLE 28 Number of tones Number of units Total number of tones RRU 114 4456 IRU 7 6 42 left guard 6 right 5 guard DC 3 512

Referring to the left side of FIG. 7, left guardtone/IRU(7)/RRU(114)/IRU(7)/RRU(114)/IRU(7)/DCtone/IRU(7)/RRU(114)/IRU(7)/RRU(114)/IRU(7)/right guard tone may beallocated within the 40 MHz bandwidth.

Referring to the right side of FIG. 7, left guardtone/RRU(114)/IRU(7)/IRU(7)/RRU(114)/IRU(7)/DCtone/IRU(7)/RRU(114)/IRU(7)/IRU(7)/RRU(114)/right guard tone may beallocated within the 40 MHz bandwidth.

The above-described allocation of the RRUs and the IRUs may vary inaccordance with the number of users. In the following description, incase the number of users is equal to 1, 2, 3, 4, and 5, examples ofallocating resources to each number of users will be disclosed. Theallocation order may be varied, and it will be essentially assumed thatall resources are allocated to the user(s) within the entire bandwidth.

One (1) user: the numerology of 256 FFT (242 tones) that is used in thelegacy 80 MHz bandwidth may be applied and used in 40 MHz. 8 pilot tonesmay be included. Alternatively, 484 tones configured of a combination of4 RRUs (4RRU)+4 IRUs (4IRU) may be allocated to the user.

Two (2) users: 4 RRUs (4RRU) may be allocated to user1, and 6 IRUs(6IRU) may be allocated to user2. Each RRU may be allocated to 114tones, wherein the 114 tones include 108 data tones and 6 pilot tones.Therefore, a 4RRU may be allocated to 432(108*4) tones as the data tonesand may be allocated to 24(6*4) tones as the pilot tones. Each IRU maybe allocated to 7 tones, wherein the 7 tones include 6 data tones and 1pilot tone. Therefore, a 6IRU may be allocated to 36(6*6) tones as thedata tones and may be allocated to 6(1*6) tones as the pilot tones.

Three (3) users: a RRU may be allocated to user1, a 3RRU may beallocated to user2, and a 6IRU may be allocated to user3. Alternatively,a 2RRU may be allocated to user1, a 2RRU may be allocated to user2, anda 6IRU may be allocated to user3. Each RRU may be allocated to 114tones, wherein the 114 tones include 108 data tones and 6 pilot tones.Each IRU may be allocated to 7 tones, wherein the 7 tones include 6 datatones and 1 pilot tone. Alternatively, the IRU may be segmented tosmaller segments and then be allocated to each user.

Four (4) users˜seven(7) users: since the RRU size is equal to 114 tones,this structure may easily support the legacy interleaver size.Therefore, the RRUs and the IRUs may be allocated to each of theplurality of users by using diverse combinations.

The above-described allocation of RRU/IRU in accordance with the numberof users within the 40 MHz bandwidth is merely exemplary, and,therefore, the RRU/IRU may be allocated by using diverse methods, andsuch exemplary embodiments are also included in the scope of the presentinvention.

FIG. 8 is a conceptual view illustrating a resource allocation accordingto an exemplary embodiment of the present invention.

FIG. 8 discloses a resource allocation of {RRU, IRU}={114 tones, 7tones} for the 80 MHz bandwidth, which is shown below in Table 29.

TABLE 29 Number of tones Number of units Total number of tones RRU 114 8912 IRU 7 14 98 left guard 6 right 5 guard DC 3 1024

Referring to the left side of FIG. 8, left guardtone/IRU(7)/RRU(114)/IRU(7)/IRU(7)/RRU(114)/IRU(7)/IRU(7)/RRU(114)/IRU(7)/IRU(7)/RRU(114)/DCtone/RRU(114)/IRU(7)/IRU(7)/RRU(114)/IRU(7)/IRU(7)/RRU(114)/IRU(7)/IRU(7)/RRU(114)/IRU(7)/rightguard tone may be allocated within the 80 MHz bandwidth.

Referring to the right side of FIG. 8, left guardtone/RRU(114)/IRU(7)/IRU(7)/RRU(114)/IRU(7)/IRU(7)/RRU(114)/IRU(7)/IRU(7)/RRU(114)/IRU(7)/DCtone/IRU(7)/RRU(114)/IRU(7)/IRU(7)/RRU(114)/IRU(7)/IRU(7)/RRU(114)/IRU(7)/IRU(7)/RRU(114)/rightguard tone may be allocated within the 80 MHz bandwidth.

The above-described allocation of the RRUs and the IRUs may vary inaccordance with the number of users. In the following description, incase the number of users is equal to 1, 2, 3, 4, and 5, examples ofallocating resources to each number of users will be disclosed. Theallocation order may be varied, and it will be essentially assumed thatall resources are allocated to the user(s) within the entire bandwidth.

The allocation method according to the number of allocations beingallocated to users (or number of users) within the 80 MHz bandwidth maybe similar to the cases when the bandwidth corresponds to 20 MHz and 40MHz. Essentially, resource allocation to a user may be performed byusing a method of using the related art 108-size interleaver for theinterleaving of 108 data tone (or data subcarrier) units.

One (1) user: the numerology of 256 FFT (242 tones) that is used in thelegacy 80 MHz bandwidth may be applied and used in 80 MHz. 8 pilot tonesmay be included. Alternatively, 1010 tones configured of a combinationof 8 RRUs (8RRU)+14 IRUs (14IRU) may be allocated to the user.

Two (2) users: 8 RRUs (8RRU) may be allocated to user1, and 14 IRUs(14IRU) may be allocated to user2. Each RRU may be allocated to 114tones, wherein the 114 tones include 108 data tones and 6 pilot tones.Therefore, a 8RRU may be allocated to 864(108*8) tones as the data tonesand may be allocated to 48(6*8) tones as the pilot tones. Each IRU maybe allocated to 7 tones, wherein the 7 tones include 6 data tones and 1pilot tone. Therefore, a 14IRU may be allocated to 84(6*14) tones as thedata tones and may be allocated to 14(1*14) tones as the pilot tones.

Three (3) users: a 4RRU may be allocated to user1, a 4RRU may beallocated to user2, and a 14IRU may be allocated to user3. Each RRU maybe allocated to 114 tones, wherein the 114 tones include 108 data tonesand 6 pilot tones. Each IRU may be allocated to 7 tones, wherein the 7tones include 6 data tones and 1 pilot tone. Alternatively, the IRU maybe segmented to smaller segments and then be allocated to each user.

Four (4) users˜seven (7) users: since the RRU size is equal to 114tones, this structure may easily support the legacy interleaver size.Therefore, the RRUs and the IRUs may be allocated to each of theplurality of users by using diverse combinations.

The above-described allocation of RRU/IRU in accordance with the numberof users within the 80 MHz bandwidth is merely exemplary, and,therefore, the RRU/IRU may be allocated by using diverse methods, andsuch exemplary embodiments are also included in the scope of the presentinvention.

Hereinafter, a method for signaling information corresponding to theresource allocation based on RRU/IRU will be disclosed in the exemplaryembodiments of the present invention.

FIG. 9 is a conceptual view illustrating a method for signalinginformation corresponding to RRU/IRU based resource allocation accordingto an exemplary embodiment of the present invention.

FIG. 9 discloses a method for singling information corresponding toRRUs/IRUs that are allocated for the downlink transmission to the userand/or the uplink transmission of the user.

Referring to FIG. 9, in order to effectively perform signaling of theinformation corresponding to two different resource units (e.g., RRU,IRU), first of all, the same type of RUs may be grouped and aligned (orordering of the same type of RUs may be performed) within a logicaldomain.

According to the exemplary embodiment of the present invention, astructure wherein group1 900, which corresponds to a group of RRUshaving a relatively larger size within the logical domain, has a higherpriority, and wherein group1 900 is followed by group2 950, whichcorresponds to a group of IRUs having a relatively smaller size, may beconfigured. Within a group, alignment (or ordering) may be performed inaccordance with the allocated subbands or in accordance with theallocated indexes. The allocation order within the logical domain may bevaried in accordance with the system environment and the supportedtraffic situation.

A bitmap signaling the resource allocation information (hereinafterreferred to as a resource allocation signaling bitmap) may includeindicator1 for group1 900 and indicator2 for group2 950. Indicator 1 andindicator2 may be included in the resource allocation signaling bitmapby being divided into separate bitmaps.

For example, in case a specific STA is allocated with RRU2 920 and RRU3930, ‘01100 . . . ’ may be used for the resource allocation asindicator1 for group1 900. Additionally, when a specific STA isallocated with IRU1 960 and IRU2 970, ‘1100 . . . ’ may be used for theresource allocation as indicator2 for group2 950.

The signaling for each of group1 900 and group2 950 may be transmittedthrough a resource allocation signaling bitmap, which is configured tohave a single structure. In this case, the resource allocation signalingbitmap may be interpreted based on boundary information corresponding tothe bits for group1 900 and the bits for group2 950 within a singleresource allocation signaling bitmap.

For example, in case the ordering of the RRU is performed firsthand,information on the number of RRUs and information on the end position ofeach RRU may be transmitted through a signaling field in advance, asresource allocation signaling bitmap interpretation information, beforetransmitting the resource allocation signaling bitmap.

Most particularly, for example, in case a resource allocation signalingbitmap including the resource allocation information is transmitted froma second signaling field (e.g., high efficiency (HE)-signal (SIG)2field) that is included in a PPDU header of a physical protocol dataunit (PPDU), the above-described resource allocation signaling bitmapinterpretation information may be transmitted from a first signal field(e.g., HE-SIG1 field), which is transmitted before the second signalfield.

In case the resource allocation signaling bitmap interpretationinformation is transmitted from the first signal field, decodingcomplexity of the resource allocation signaling bitmap, which istransmitted through the second signal field, may be reduced.Alternatively, the resource allocation signaling bitmap interpretationinformation and the resource allocation signaling bitmap may both betransmitted to the second signal field, and, when performing informationparsing, the resource allocation signaling bitmap interpretationinformation may first be decoded in the second signal field, and,afterwards, the resource allocation signaling bitmap may be decodedbased on the decoded bitmap interpretation information.

In case the resource allocation signaling bitmap is used, a problem mayoccur due to an overhead caused by the bitmap. Therefore, according tothe exemplary embodiment of the present invention, in order to reducethe overhead, the number of RUs may be indicated based on an indexingmethod. For example, in case 4 RRUs and 2 IRUs are allocated within theentire bandwidth, the allocation for the 4 RRUs may be indicated byusing the indexing method. For example, the 4 RRUs may be expressed as11 in case the bits for indexing the number of RUs is equal to 2 bits(00 in case the number of bits is equal to 0), 011 in case the bits forindexing the number of RUs is equal to 3 bits, and 0011 in case the bitsfor indexing the number of RUs is equal to 4 bits (the bits may besupported as a single structure up to the bandwidth of 80 MHz).

Additionally, according to the exemplary embodiment of the presentinvention, the resource allocation information that is allocated to theuser may also indicated based on offset information and lengthinformation. For example, in case RRU2 and RRU3 are allocated for anSTA, the resource allocation information may be signaled to the STAbased on the information on a start offset(=1) and the information onthe length(=2). The STA may acquire information on the RRUs that areallocated for the STA based on the information on the start offset andthe information on the length.

If the entire bandwidth is equal to 20 MHz, the information on the startoffset may be equal to 2 bits, and the information on the length may beequal to 2 bits. In the example presented above, wherein the startoffset is equal to 1 and the length is equal to 2, the information onthe start offset may be expressed as a bit value of ‘01’, and theinformation on the length may be expressed as a bit value of ‘10’.

Considering the case when the entire bandwidth is extended to up to 80MHz, the information on the start offset may be equal to 4 bits, and theinformation on the length may be equal to 4 bits. In the examplepresented above, wherein the start offset is equal to 1 and the lengthis equal to 2, the information on the start offset may be expressed as abit value of ‘0001’, and the information on the length may be expressedas a bit value of ‘0010’. Similarly, the signaling of the IRUs may alsobe performed based on the information on the start offset and theinformation on the length.

Resource allocation of RRU1, which is allocated to 56 tones (orsubcarriers), and RRU2, which is allocated to 26 tones (or subcarriers),may be supported by differently setting up the minimum granularity inaccordance with the size of the bandwidth.

More specifically, although a gain of full scalability can be acquiredindependently from the size of the bandwidth, by setting the minimumgranularity to be subordinate to the size of the bandwidth, thesignaling overhead may be reduced. For example, the minimum granularitycorresponding to each of 20 MHz, 40 MHz, and 80 MHz may respectively beequal to RRUs of 26 tones, RRUs of 56 tones, and RRUs of 56 tones.Moreover, in another example, the minimum granularity corresponding toeach of 20 MHz, 40 MHz, and 80 MHz may respectively be equal to RRUs of26 tones, RRUs of 26 tones, and RRUs of 56 tones.

Hereinafter, the exemplary embodiment of the present invention disclosesRRUs and IRUs configuring the data tone and an interleaver size forinterleaving the data tones and the pilot tones. According to theexemplary embodiment of the present invention, the number of pilot tonesbeing included in a RRU may vary in accordance with the number ofallocated RRUs. More specifically, the number of data tones and thenumber of pilot tones within a RRU may vary in accordance with thenumber of RRUs being allocated to the user.

In case RRUs based on 56 tones and IRUs based on 8 tones are used, thenumber of data tones and the number of pilot tones being allocated toone RRU may vary in accordance with the number of RRUs being allocatedto the user within a bandwidth of 20 MHz as shown below in Table 30.

TABLE 30 Number of Number of data tones Number of pilot tones allocatedRRUs per RRU per RRU Interleaver size 1 52 4 52 (data interleaver sizeused in the legacy 20 MHz 64 FFT) 2 54 (total 108 tones for 2 (total 4tones for 108 (data interleaver size used 2RRUs) 2RRUs) in the legacy 40MHz 128 FFT) 3 52 for one block (1 16 (DC: 5, GS: 11 or Two blockinterleaving RRU), 54 for the other DC: 3, GS: 13) (1RRU + 2RRUs):application block (2 RRUs) 4 for 1RRU, 2 for each of data interleaversize of 52 of 2RRUs (total 8 tones for 1RRU, application of data for3RRUs) interleaver size of 108 for 2RRUs 4 (option-1) 54 (total 216tones for 2 (total 8 tones for Two block interleaving 4RRUs) 4RRUs)(2RRUs + 2RRUs): application of data interleaver size of 108 for eachblock 4 (option-2) Entire BW allocation Entire BW allocation 234(application of data (re-usage of (re-usage of pilot used interleaverused in the legacy numerology used in in the legacy 80 MHz 80 MHz 256FFT) the legacy 80 MHz 256 256 FFT) FFT)

In case the RU size is equal to 56 tones (or in case of a RRU structurebased on 56 subcarriers), the data tones and the pilot tones may beallocated as described above. Essentially, in order to use theinterleaver size (108, 52, etc.) that was used in the legacy wirelessLAN system, data tones and pilot tones may be allocated within at leastone of the allocated RRUs. For reference, in the legacy wireless LAN,64FFT was used for the bandwidth of 20 MHz, and interleaving of datatones based on the interleaver size of 108 was performed. Additionally,in the legacy wireless LAN, 128FFT was used for the bandwidth of 40 MHz,and interleaving of data tones based on the interleaver having the sizeof 108 was performed.

More specifically, in case the number of RRUs being allocated to the STAis equal to 1, among the 56 tones allocated to the RRU, 52 tones may beused as the data tones, and the remaining 4 tones may be used as thepilot tones. In case such allocation of data tones and pilot tones isused, the interleaving for 52 data tones may be performed based on theinterleaver having the size of 52.

Additionally, in case the number of RRUs being allocated to the STA isequal to 2, among the 56 tones allocated to the RRU, 54 tones may beused as the data tones, and the remaining 2 tones may be used as thepilot tones. More specifically, the 2RRU may be allocated to 108 datatones and 4 pilot tones. In case such allocation of data tones and pilottones is used, the interleaving for 108 data tones may be performedbased on the interleaver having the size of 108.

Additionally, in case the number of RRUs being allocated to the STA isequal to 3, RRU1, wherein, among the allocated 56 tones, 52 tones may beused as the data tones, and the remaining 4 tones may be used as thepilot tones, and RRU2, wherein, among the allocated 56 tones, 54 tonesmay be used as the data tones, and the remaining 2 tones may be used asthe pilot tones, may be used. More specifically, among the 3 RRUs, oneRRU may correspond to RRU1 (52 data tones and 4 pilot tones) and theremaining two RRUs may correspond to RRU2 (54 data tones and 2 pilottones).

More specifically, 3RRU may be allocated to 160 data tones (108 datatones+52 data tones) and 8 pilot tones. In case such data tone and pilottone allocation is used, a two-block interleaving may be performed. Morespecifically, interleaving for 108 data tones based on an interleaverhaving the size of 108 and interleaving for 52 data tones based on aninterleaver having the size of 52 may be performed.

Additionally, in case the number of RRUs being allocated to the STA isequal to 4, among the 56 tones allocated to each RRU, 54 tones may beused as the data tones, and the remaining 2 tones may be used as thepilot tones. More specifically, the 4RRU may be allocated to 216 datatones (108 data tones+108 data tones) and 8 pilot tones. In case suchdata tone and pilot tone allocation is used, a two-block interleavingmay be performed. In case such allocation of data tones and pilot tonesis used, the interleaving for 108 data tones may be performed based onthe interleaver having the size of 108. More specifically, interleavingfor a first set of 108 data tones based on an interleaver having thesize of 108 and interleaving for a second set of 108 data tones based onan interleaver having the size of 108 may be performed.

Alternatively, in case the number of RRUs being allocated to the STA isequal to 4, 256 IFFT/FFT corresponding to the legacy 80 MHz bandwidthmay be used. More specifically, 234 data tones and 8 pilot tones may beused, and the interleaver that was used for the 256 IFFT/FFTcorresponding to the legacy 80 MHz bandwidth may perform interleavingfor 234 data tones.

Based on the above-described allocation of data tones and pilot tones inaccordance with the number of allocated RRUs within the bandwidth of 20MHz, the allocation of data tones and pilot tones in accordance with thenumber of allocated RRUs within the bandwidths of 40 MHz and 80 MHz maybe performed.

According to the exemplary embodiment of the present invention, theallocated number of data tones and the allocated number of pilot tonesin accordance with the allocated RRUs within the bandwidth of 40 MHz maybe determined based on the allocation of data tones and pilot tones inaccordance with the number of RRU allocations within the bandwidth of 20MHz, as described above in Table 30.

First of all, in case the number of RRU allocations within the bandwidthof 40 MHz is equal to 1 to 4, the data tones and the pilot tones may beallocated by using the same method as the method used in the case whenthe number of RRU allocations within the bandwidth of 20 MHz is equal to1 to 4.

In case the number of RRU allocations within the bandwidth of 40 MHz isequal to 5 to 7, the allocation method of data tones and pilot tonescorresponding to the case when the number of RRU allocations within thebandwidth of 20 MHz is equal to 1 to 4 may be used.

For example, in case the number of RRUs allocated within the bandwidthof 40 MHz is equal to 5, the above-described allocation of data tonesand pilot tones (option 1 or option 2) corresponding to 4 RRUs withinthe bandwidth of 20 MHz may be applied to the 4 RRUs, and theabove-described allocation of data tones and pilot tones correspondingto one RRU within the bandwidth of 20 MHz may be applied to the one RRU.

Additionally, in case the number of RRUs allocated within the bandwidthof 40 MHz is equal to 6, the above-described allocation of data tonesand pilot tones (option 1 or option 2) corresponding to 4 RRUs withinthe bandwidth of 20 MHz may be applied to the 4 RRUs, and theabove-described allocation of data tones and pilot tones correspondingto 2 RRUs within the bandwidth of 20 MHz may be applied to the remaining2 RRUs.

Additionally, in case the number of RRUs allocated within the bandwidthof 40 MHz is equal to 7, the above-described allocation of data tonesand pilot tones (option 1 or option 2) corresponding to 4 RRUs withinthe bandwidth of 20 MHz may be applied to the 4 RRUs, and theabove-described allocation of data tones and pilot tones correspondingto 3 RRUs within the bandwidth of 20 MHz may be applied to the remaining3 RRUs.

Additionally, in case the number of RRUs allocated within the bandwidthof 40 MHz is equal to 8, the above-described allocation of data tonesand pilot tones (option 1 or option 2) corresponding to 4 RRUs withinthe bandwidth of 20 MHz may be repeated and applied to the 8 RRUs.

Additionally, according to the exemplary embodiment of the presentinvention, for the data tones and the pilot tones according to thenumber of RRU allocations within the bandwidth of 80 MHz, the data tonesand the pilot tones according to the above-described number of RRUallocations within the bandwidth of 40 MHz may be repeated and applied.

First of all, in case the number of RRU allocations within the bandwidthof 80 MHz is equal to 1 to 8, the data tones and the pilot tones may beallocated by using the same method as the method used in the case whenthe number of RRU allocations within the bandwidth of 40 MHz is equal to1 to 8.

In case the number of RRU allocations within the bandwidth of 80 MHz isequal to 9 to 15, the above-described allocation of data tones and pilottones corresponding to 8 RRUs within the bandwidth of 40 MHz may beapplied to the 8 RRUs, and the above-described allocation of data tonesand pilot tones corresponding to 1 to 7 RRUs within the bandwidth of 40MHz may be applied to the remaining RRUs.

Additionally, in case the number of RRUs allocated within the bandwidthof 80 MHz is equal to 16, the above-described allocation of data tonesand pilot tones corresponding to 8 RRUs within the bandwidth of 40 MHzmay be repeated and applied to the 16 RRUs.

In case RRUs based on 26 tones and IRUs based on 8 tones are used, thenumber of data tones and the number of pilot tones being allocated toone RRU may vary in accordance with the number of RRUs being allocatedto the user within a bandwidth of 20 MHz as shown below in Table 31.

TABLE 31 Number of Number of data tones Number of pilot tones allocatedRRUs per RRU per RRU Interleaver size 1 24 2 24 (data interleaver sizeused in the legacy 802.11ah 1 MHz 34 FFT) 2 24 (total 48 tones for 2(total 4 tones for Two block interleaving (1RU + 2RUs) 2RUs) 1RU): eachblock uses of data interleaver having the size of 24 3 24 (total 72tones for 2 (total 6 tones for Three block interleaving (1RU + 3RUs)3RUs) 1RU + 1RU): each block uses of data interleaver having the size of24 4 24 (total 96 tones for 2 (total 8 tones for Four block interleaving(1RU + 4RUs) 4RUs) 1RU + 1RU + 1RU): each block uses of data interleaverhaving the size of 24 . . . . . . . . . 8 (option-1) 24 (total 192 tones2 (total 16 tones for Eight block interleaving for 8RUs) 8RUs) (1RU +1RU + 1RU + 1RU . . . + 1RU): each block uses of data interleaver havingthe size of 24 8 (option-2) Entire BW allocation Entire BW allocation234 (data interleaver used in the (re-usage of (re-usage of pilot usedlegacy 80 MHz 256 FFT) numerology used in in the legacy 80 MHz thelegacy 80 MHz 256 FFT) 256 FFT)

In case the RU size is equal to 24 tones (or in case of a RRU structurebased on 24 subcarriers), the data tones and the pilot tones may beallocated as described above. Essentially, in order to use theinterleaver size (108, 52, 24, etc.) that was used in the legacywireless LAN system, data tones and pilot tones may be allocated withinat least one of the allocated RRUs.

More specifically, in case the number of RRUs being allocated to the STAis equal to 1, among the 26 tones allocated to the RRU, 24 tones may beused as the data tones, and the remaining 2 tones may be used as thepilot tones. In case such allocation of data tones and pilot tones isused, the interleaving for 24 data tones may be performed based on theinterleaver having the size of 24.

Additionally, in case the number of RRUs being allocated to the STA isequal to 2, among the 26 tones allocated to the RRU, 24 tones may beused as the data tones, and the remaining 2 tones may be used as thepilot tones. More specifically, 2 RRUs (2RRU) may be allocated to 48data tones and 4 pilot tones. In case such allocation of data tones andpilot tones is used, two-block interleaving that is based on theinterleaver having the size of 24 may be performed for the 24 data tonesincluded in each 2RRU.

Additionally, in case the number of RRUs being allocated to the STA isequal to 3, among the 26 tones allocated to each RRU, 24 tones may beused as the data tones, and the remaining 2 tones may be used as thepilot tones. More specifically, 3 RRUs (3RRU) may be allocated to 72data tones and 6 pilot tones. In case such allocation of data tones andpilot tones is used, three-block interleaving that is based on theinterleaver having the size of 24 may be performed for the 24 data tonesincluded in each 3RRU.

Additionally, in case the number of RRUs being allocated to the STA isequal to 4, among the 26 tones allocated to each RRU, 24 tones may beused as the data tones, and the remaining 2 tones may be used as thepilot tones. More specifically, 4 RRUs (4RRU) may be allocated to 96data tones and 8 pilot tones. In case such allocation of data tones andpilot tones is used, four-block interleaving that is based on theinterleaver having the size of 24 may be performed for the 24 data tonesincluded in each 4RRU.

The allocation of data tones/pilot tones for cases when the number ofRRUs is equal to 5 to 8 may be performed by using the same method.

In case the number of RRUs being allocated to the STA is equal to 8,among the 26 tones allocated to each RRU, 24 tones may be used as thedata tones, and the remaining 2 tones may be used as the pilot tones.More specifically, 8 RRUs (8RRU) may be allocated to 192 data tones and16 pilot tones. In case such allocation of data tones and pilot tones isused, eight-block interleaving that is based on the interleaver havingthe size of 24 may be performed for the 24 data tones included in each8RRU.

Alternatively, in case the number of RRUs being allocated to the STA isequal to 8, 256 IFFT/FFT corresponding to the legacy 80 MHz bandwidthmay be used. More specifically, 234 data tones and 8 pilot tones may beused, and the interleaver that was used for the 256 IFFT/FFTcorresponding to the legacy 80 MHz bandwidth may be used for theinterleaving of 234 data tones.

Based on the above-described allocation of data tones and pilot tones inaccordance with the number of allocated RRUs within the bandwidth of 20MHz, the allocation of data tones and pilot tones in accordance with thenumber of allocated RRUs within the bandwidths of 40 MHz and 80 MHz maybe performed.

According to the exemplary embodiment of the present invention, theallocated number of data tones and the allocated number of pilot tonesin accordance with the allocated RRUs within the bandwidth of 40 MHz maybe determined based on the allocation of data tones and pilot tones inaccordance with the number of RRU allocations within the bandwidth of 20MHz, as described above in Table 31.

First of all, in case the number of RRU allocations within the bandwidthof 40 MHz is equal to 1 to 8, the data tones and the pilot tones may beallocated by using the same method as the method used in the case whenthe number of RRU allocations within the bandwidth of 20 MHz is equal to1 to 8.

In case the number of RRU allocations within the bandwidth of 40 MHz isequal to 9 to 15, the allocation method of data tones and pilot tonescorresponding to the case when the number of RRU allocations within thebandwidth of 20 MHz is equal to 1 to 8 may be used.

For example, in case the number of RRUs allocated within the bandwidthof 40 MHz is equal to 9, the above-described allocation of data tonesand pilot tones (option 1 or option 2) corresponding to 8 RRUs withinthe bandwidth of 20 MHz may be applied to the 8 RRUs, and theabove-described allocation of data tones and pilot tones correspondingto one RRU within the bandwidth of 20 MHz may be applied to the one RRU.

Additionally, in case the number of RRUs allocated within the bandwidthof 40 MHz is equal to 10, the above-described allocation of data tonesand pilot tones (option 1 or option 2) corresponding to 8 RRUs withinthe bandwidth of 20 MHz may be applied to the 8 RRUs, and theabove-described allocation of data tones and pilot tones correspondingto 2 RRUs within the bandwidth of 20 MHz may be applied to the remaining2 RRUs. Additionally, in case the number of RRUs allocated within thebandwidth of 40 MHz is equal to 11, the above-described allocation ofdata tones and pilot tones (option 1 or option 2) corresponding to 8RRUs within the bandwidth of 20 MHz may be applied to the 8 RRUs, andthe above-described allocation of data tones and pilot tonescorresponding to 3 RRUs within the bandwidth of 20 MHz may be applied tothe remaining 3 RRUs.

In case the number of RRUs being allocated within the bandwidth of 40MHz by using the above-described method is equal to 12, 13, 14, and 15,allocation of data tones and pilot tones (option 1 or option 2) for 8RRUs within the bandwidth of 20 MHz may be applied for 8 RRUs, andallocation of data tones and pilot tones (option 1 or option 2) for 4RRUs, 5 RRUs, 6 RRUs, and 7 RRUs within the bandwidth of 20 MHz may berespectively applied for the remaining 4 RRUs, 5 RRUs, 6 RRUs, and 7RRUs.

Additionally, in case the number of RRUs allocated within the bandwidthof 40 MHz is equal to 16, the above-described allocation of data tonesand pilot tones (option 1 or option 2) corresponding to 8 RRUs withinthe bandwidth of 20 MHz may be repeated and applied to the 16 RRUs.

Additionally, according to the exemplary embodiment of the presentinvention, for the data tones and the pilot tones according to thenumber of RRU allocations within the bandwidth of 80 MHz, the data tonesand the pilot tones according to the above-described number of RRUallocations within the bandwidth of 40 MHz may be repeated and applied.

First of all, in case the number of RRU allocations within the bandwidthof 80 MHz is equal to 1 to 16, the data tones and the pilot tones may beallocated by using the same method as the method used in the case whenthe number of RRU allocations within the bandwidth of 40 MHz is equal to1 to 16.

In case the number of RRU allocations within the bandwidth of 80 MHz isequal to 17 to 31, the above-described allocation of data tones andpilot tones corresponding to 16 RRUs within the bandwidth of 40 MHz maybe applied to the 16 RRUs, and the above-described allocation of datatones and pilot tones corresponding to 1 to 15 RRUs within the bandwidthof 40 MHz may be applied to the remaining RRUs.

Additionally, in case the number of RRUs allocated within the bandwidthof 80 MHz is equal to 32, the above-described allocation of data tonesand pilot tones corresponding to 16 RRUs within the bandwidth of 40 MHzmay be repeated and applied to the 32 RRUs.

In case the IRU size is equal to 8 tones (in case of an IRU based on 8subcarriers), the number of data tones is equal to 7, and the number ofpilot tones is equal to 1. Such numerology may be applied to the IRUregardless of the number of IRUs being allocated within the entirebandwidth. In case the size of one IRU is equal to 8 tones (or 8subcarriers), the minimum IRU granularity may be equal to 8 tones.Alternatively, the logical 2IRU corresponding to 16 tones may also beused as minimum IRU granularity. In this case, the size of the data tonemay be equal to a multiple of 14.

In case the IRU size is equal to 9 tones (in case of an IRU based on 9subcarriers), the number of data tones is equal to 8, and the number ofpilot tones is equal to 1. Such numerology may be applied to the IRUregardless of the number of IRUs being allocated within the entirebandwidth. In case the size of one IRU is equal to 9 tones (or 9subcarriers), the minimum IRU granularity may be equal to 9 tones.Alternatively, the logical 2IRU corresponding to 18 tones may also beused as minimum IRU granularity. In this case, the size of the data tonemay be equal to a multiple of 16.

Additionally, according to the exemplary embodiment of the presentinvention, resource allocation may also be performed based on acombination of diverse resource units.

More specifically, a first resource unit having the size of 56 tones, asecond resource unit having the size of 26 tones, and a third resourceunit having the size of 14 tones may be defined.

Based on 242 tones for resource units within the 20 MHz bandwidth, thetone for resource units within the 40 MHz bandwidth and the 80 MHzbandwidth may be scalably increased. More specifically, 484 tones (242tones*2) for the 40 MHz bandwidth and 968 tones (242 tones*4) for the 80MHz bandwidth may be used as the first resource unit and the secondresource unit.

Additionally, in the 20 MHz bandwidth, among the 256 tones, theremaining 14 tones excluding the 242 tones may be allocated for the DCtones (3 tones), the left guard tones (6 tones), and the right sidetones (5 tones).

The size of the 14 tones for the DC tones, left guard tones, and theright guard tones may be identical to the size of the third resourceunit, and, since the size of the first resource unit (56 tones) is themultiple of the size of the third resource unit (14 tones), diversescalable designs may be performed.

Hereinafter, a detailed resource allocation within the 20 MHz, 40 MHz,and 80 MHz bandwidths will be disclosed.

TABLE 32 Number of Number of Total number Resource unit tones units oftones Primary resource unit 56 2 112 Secondary resource unit 26 5 130 65 3 256

Table 32 discloses a resource allocation that is based on a firstresource unit and a second resource unit in a 20 MHz bandwidth.

TABLE 33 Number of Number of Total number Resource unit tones units oftones Primary resource unit 56 4 224 Secondary resource unit 26 10 260Tertiary resource unit 14 1 14 6 5 3 512

Table 33 discloses a resource allocation that is based on a firstresource unit, a second resource unit, and a third resource unit in a 40MHz bandwidth.

TABLE 34 Number of Number of Total number Resource unit tones units oftones Primary resource unit 56 8 448 Secondary resource unit 26 20 520Tertiary resource unit 14 3 42 6 5 3 1024

Table 34 discloses a resource allocation that is based on a firstresource unit, a second resource unit, and a third resource unit in an80 MHz bandwidth.

Hereinafter, another detailed resource allocation within the 20 MHz, 40MHz, and 80 MHz bandwidths will be disclosed.

TABLE 35 Number of Number of Total number Resource unit tones units oftones Primary resource unit 56 2 112 Secondary resource unit 26 5 130 65 3 256

Table 35 discloses a resource allocation that is based on a firstresource unit and a second resource unit in a 20 MHz bandwidth.

TABLE 36 Number of Number of Total number Resource unit tones units oftones Primary resource unit 56 4 224 Secondary resource unit 26 10 260Tertiary resource unit 14 1 14 6 5 3 512

Table 36 discloses a resource allocation that is based on a firstresource unit, a second resource unit, and a third resource unit in a 40MHz bandwidth.

TABLE 37 Number of Number of Total number Resource unit tones units oftones Primary resource unit 56 8 448 Secondary resource unit 26 20 520Tertiary resource unit 14 3 42 6 5 3 1024

Table 37 discloses a resource allocation that is based on a firstresource unit, a second resource unit, and a third resource unit in an80 MHz bandwidth.

Also, a combination shown below in Table 38 may be used for the 20 MHzbandwidth.

TABLE 38 Number of Number of Total number Resource unit tones units oftones Primary resource unit 56 2 112 Secondary resource unit 13 10 130 65 3 256

At this point, one primary resource unit of 56 tones may be divided inunits of 28 tones, so as to be divided into 2 resource units of 28 tonesand then used, and 2 secondary resource units of 13 tones may be groupedto be used as a resource unit of 26 tones. Moreover, the primaryresource units and the secondary resource units may be grouped so as tobe used as a resource unit of 242 tones.

Also, a combination shown below in Table 39 to Table 42 may be used forthe 40 MHz bandwidth.

TABLE 39 Number of Number of Total number Resource unit tones units oftones Primary resource unit 56 4 224 Secondary resource unit 26 10 260 65 17 512

TABLE 40 Number of Number of Total number Resource unit tones units oftones Primary resource unit 56 6 336 Secondary resource unit 26 6 260 65 9 512

TABLE 41 Number of Number of Total number Resource unit tones units oftones Primary resource unit 28 14 392 Secondary resource unit 13 8 104 65 5 512

TABLE 42 Number of Number of Total number Resource unit tones units oftones Primary resource unit 57 6 112 Secondary resource unit 26 6 156 65 3 512

Referring to Table 41, 2 secondary resource units of 13 tones may begrouped to be used as a resource unit of 26 tones. Also, referring toTable 42, 2 primary resource units of 57 tones may be grouped to be usedas a resource unit of 114 tones.

Also, a combination shown below in Table 43 to Table 46 may be used forthe 80 MHz bandwidth.

TABLE 43 Number of Number of Total number Resource unit tones units oftones Primary resource unit 56 8 448 Secondary resource unit 13 42 546 65 19 1024

TABLE 44 Number of Number of Total number Resource unit tones units oftones Primary resource unit 56 10 560 Secondary resource unit 13 34 4426 5 11 1024

TABLE 45 Number of Number of Total number Resource unit tones units oftones Primary resource unit 57 14 798 Secondary resource unit 26 8 208 65 7 1024

TABLE 46 Number of Number of Total number Resource unit tones units oftones Primary resource unit 114 1 114 Secondary resource unit 56 16 8966 5 3 1024

Referring to Table 43 and Table 44, 2 secondary resource units of 13tones may be grouped to be used as a resource unit of 26 tones. And,referring to Table 45, 2 primary resource units of 57 tones may begrouped to be used as a resource unit of 114 tones.

In the wireless LAN system according to the exemplary embodiment of thepresent invention, a PPDU may be generated based on a IFFT size that isN times (e.g., N=4) larger than the legacy wireless LAN system and maydecode the PPDU based on a FFT size that is N times larger. Such FFTsize/IFFT size that are N times larger may be applied to the remainingpart (payload) (MAC protocol data unit (MPDU)) of the PPDU excluding thePPDU header or may be applied some of the fields in the PPDU header andpayload. In case the IFFT that is N times larger is used, the length ofa valid symbol for the transmission of the PPDU may be increased to Ntimes its initial length. Additionally, even if the IFFT that is N timeslarger is not applied for the OFDM symbol transmitting the HE-SIG of thePPDU, a longer cyclic prefix (CP) may be applied to the OFDM symbol,thereby enhancing the transmission coverage.

In the wireless LAN system according to the exemplary embodiment of thepresent invention, diverse CP lengths may be used. For example, thelength of the CP may be equal to 0.4 μs, 0.8 μs, 1.6 μs, 2.4 μs, 3.2 μs,and so on. Depending upon the communication environment, different CPsmay be used. In case a plurality of CPs are optionally used, thethroughput of the wireless LAN system may be enhanced, and, mostparticularly, the performance of the wireless LAN system in an outdoorenvironment may be enhanced. For example, in order to increase thethroughput of the wireless LAN system, a CP of 0.8 μs is used, and inorder to enhance the performance of the wireless LAN system in anoutdoor environment, a CP of 3.2 μs may be used. Moreover, the wirelessLAN system according to the exemplary embodiment of the presentinvention may support uplink multi-user (UL MU) transmission. Thetransmission of uplink data within an overlapping time resource may beperformed by each of the plurality of STAs based on the UL MUtransmission. An uplink indicates a transmission link from the STA tothe AP, and a downlink indicates a transmission link from the AP to theSTA.

Additionally, in the wireless LAN system according to the exemplaryembodiment of the present invention, a pilot (pilot signal or pilot tone(or pilot subcarrier)) may be categorized as a common pilot and adedicated pilot. A common pilot may be shared by all users and maygenerally be used in a downlink. As a pilot dedicated to a specificuser, a dedicated pilot may generally be used in an uplink. Thededicated pilot may also be used in a downlink.

The number and positions of the pilots may be determined in accordancewith a resource allocation method and a subband granularity.

Most particularly, in the wireless LAN system according to the exemplaryembodiment of the present invention, a scalable resource allocation maybe supported in accordance with a minimum resource granularity. In caseof a downlink transmission, a pilot may be allocated to the outside ofeach resource unit, and, in case of an uplink transmission, a pilot maybe allocated to the inside of each resource unit. A pilot structure thatwas used in the legacy wireless LAN system may also be used.

Two different methods may be discussed for the resource allocation(subband granularity).

Method 1 may define resource units re-using previous resource units andmay additionally define a new minimum resource unit. For example, incase 256FFT/IFFT is used, resources units of 26 tones, 56 tones, 114tones, and 242 tones, which correspond to the sizes of the previousresource units, and a resource unit of 14 tones, which corresponds tothe new minimum resource unit, may be defined. Such resource units maybe supported by the encoding procedure and the interleaving procedure ofthe legacy wireless LAN system. Each resource unit includes data tonesand pilot tones.

Method 2 may define resource units so as to allow a scalable design ofthe minimum resource granularity to be carried out. For example, in casethe minimum granularity of the resource unit is equal to X tones, thesize of an allocatable resource unit may be equal to a multiple of X,X*{1, 2, 3, 4, . . . }. For example, the resource unit corresponding tothe minimum granularity may include 12 data tones. In case 12 multipleunits of the data tones are included in the resource unit, diverse MCSmay be supported in the resource unit.

A pilot may be included or may not be included depending upon whetherthe pilot is in common usage or in dedicated usage. In case suchscalable design is used, if an adequate minimum resource granularity iswell-selected, the minimum resource granularity may be flexibly appliedto most part of the data unit. Moreover, a resource unit that is basedon the minimum resource granularity may be easily scheduled inaccordance with the sizes of diverse traffic data.

A resource unit is that is defined in order to allow the scalable designof Method 2 to be carried out, the following criteria may beadditionally considered and determined.

In order to avoid non-conformity between the coverage of the downlinkand the coverage of the uplink, resource units may be defined so thatcommonality exists between downlink resources and uplink resources.

Additionally, excessively small resource granularity may increaseoverhead for scheduling and signaling. Therefore, the minimum resourcegranularity shall be determined while considering such overhead forscheduling and signaling.

Moreover, the overhead caused by pilots shall also be considered. Incase a size that is N times the IFFT size is applied for the commonpilot, since the number of tones is also increased by N times, therelative overhead caused by the pilot may be reduced.

Hereinafter, a resource allocation method of a dedicated resource unitand a resource allocation method of a common resource unit will bedisclosed. Herein, a dedicated resource unit corresponds to a resourceunit including pilot tones, and a common resource unit corresponds to aresource unit that does not include any pilot tones.

First of all, a scalable resource allocation based on the dedicatedresource unit will be disclosed.

For example, the dedicated resource unit may correspond to a resourceunit of 14 tones. The resource unit of 14 tones may include 12 datatones and 2 pilot tones. In a 20 MHz bandwidth, among the entire 256tones, 17 dedicated resource units may be allocated to 238 tones(14*17), and DC tones, left guard tones, and right guard tones may beallocated to the remaining 18 tones. And, in a 40 MHz bandwidth, amongthe entire 512 tones, 35 dedicated resource units may be allocated to490 tones (14*35), and DC tones, left guard tones, and right guard tonesmay be allocated to the remaining 22 tones. And, in a 80 MHz bandwidth,among the entire 1024 tones, 72 dedicated resource units may beallocated to 1008 tones (14*72), and DC tones, left guard tones, andright guard tones may be allocated to the remaining 16 tones.

As another example, the dedicated resource unit may correspond to aresource unit of 26 tones. The resource unit of 26 tones may include 24data tones and 2 pilot tones. In a 20 MHz bandwidth, among the entire256 tones, 9 dedicated resource units may be allocated to 234 tones(26*9), and DC tones, left guard tones, and right guard tones may beallocated to the remaining 22 tones. And, in a 40 MHz bandwidth, amongthe entire 512 tones, 19 dedicated resource units may be allocated to494 tones (26*19), and DC tones, left guard tones, and right guard tonesmay be allocated to the remaining 18 tones. And, in a 80 MHz bandwidth,among the entire 1024 tones, 38 dedicated resource units may beallocated to 988 tones (26*38), and DC tones, left guard tones, andright guard tones may be allocated to the remaining 36 tones.

As yet another example, the dedicated resource unit may correspond to aresource unit of 56 tones. The resource unit of 56 tones may include 52data tones and 4 pilot tones. In a 20 MHz bandwidth, among the entire256 tones, 4 dedicated resource units may be allocated to 224 tones(56*4), and DC tones, left guard tones, and right guard tones may beallocated to the remaining 32 tones. And, in a 40 MHz bandwidth, amongthe entire 512 tones, 8 dedicated resource units may be allocated to 448tones (56*8), and DC tones, left guard tones, and right guard tones maybe allocated to the remaining 64 tones. And, in a 80 MHz bandwidth,among the entire 1024 tones, 18 dedicated resource units may beallocated to 1008 tones (56*18), and DC tones, left guard tones, andright guard tones may be allocated to the remaining 16 tones.

Different dedicated resource unit sizes may be used depending upon thebandwidth. For example, a dedicated resource unit of 14 tones or 26tones may be used in the bandwidths of 20 MHz and 40 MHz, and adedicated resource unit of 56 tones may be used in the bandwidth of 80MHz.

Hereinafter, a scalable resource allocation based on the common resourceunit will be disclosed.

For example, the dedicated resource unit may correspond to a resourceunit of 12 tones. The resource unit of 12 tones may include 12 datatones. In a 20 MHz bandwidth, among the entire 256 tones, 19 dedicatedresource units may be allocated to 228 tones (12*19), and pilot tones,DC tones, left guard tones, and right guard tones may be allocated tothe remaining 28 tones. And, in a 40 MHz bandwidth, among the entire 512tones, 40 dedicated resource units may be allocated to 480 tones(12*40), and pilot tones, DC tones, left guard tones, and right guardtones may be allocated to the remaining 32 tones. And, in a 80 MHzbandwidth, among the entire 1024 tones, 83 dedicated resource units maybe allocated to 996 tones (12*83), and pilot tones, DC tones, left guardtones, and right guard tones may be allocated to the remaining 28 tones.

As another example, the dedicated resource unit may correspond to aresource unit of 24 tones. The resource unit of 24 tones may include 24data tones. In a 20 MHz bandwidth, among the entire 256 tones, 9dedicated resource units may be allocated to 216 tones (24*9), and pilottones, DC tones, left guard tones, and right guard tones may beallocated to the remaining 40 tones. And, in a 40 MHz bandwidth, amongthe entire 512 tones, 20 dedicated resource units may be allocated to480 tones (24*20), and pilot tones, DC tones, left guard tones, andright guard tones may be allocated to the remaining 32 tones. And, in a80 MHz bandwidth, among the entire 1024 tones, 41 dedicated resourceunits may be allocated to 984 tones (24*41), and pilot tones, DC tones,left guard tones, and right guard tones may be allocated to theremaining 40 tones.

As yet another example, the dedicated resource unit may correspond to aresource unit of 36 tones. The resource unit of 36 tones may include 36data tones. In a 20 MHz bandwidth, among the entire 256 tones, 6dedicated resource units may be allocated to 216 tones (36*6), and pilottones, DC tones, left guard tones, and right guard tones may beallocated to the remaining 40 tones. And, in a 40 MHz bandwidth, amongthe entire 512 tones, 13 dedicated resource units may be allocated to468 tones (36*13), and pilot tones, DC tones, left guard tones, andright guard tones may be allocated to the remaining 44 tones. And, in a80 MHz bandwidth, among the entire 1024 tones, 27 dedicated resourceunits may be allocated to 972 tones (36*27), and pilot tones, DC tones,left guard tones, and right guard tones may be allocated to theremaining 52 tones.

As yet another example, the dedicated resource unit may correspond to aresource unit of 48 tones. The resource unit of 48 tones may include 48data tones. In a 20 MHz bandwidth, among the entire 256 tones, 4dedicated resource units may be allocated to 192 tones (48*4), and pilottones, DC tones, left guard tones, and right guard tones may beallocated to the remaining 64 tones. And, in a 40 MHz bandwidth, amongthe entire 512 tones, 10 dedicated resource units may be allocated to480 tones (48*10), and pilot tones, DC tones, left guard tones, andright guard tones may be allocated to the remaining 32 tones. And, in a80 MHz bandwidth, among the entire 1024 tones, 20 dedicated resourceunits may be allocated to 960 tones (48*20), and pilot tones, DC tones,left guard tones, and right guard tones may be allocated to theremaining 64 tones.

Hereinafter, in case STAs communicating through diverse bandwidthswithin the BSS exist, the exemplary embodiment of the present inventiondiscloses a method of using an IRU (or small tone unit (STU)) asresource for a guard tone or DC tone.

FIG. 10 is a conceptual view illustrating a resource allocationaccording to an exemplary embodiment of the present invention.

FIG. 10 discloses a method for supporting an STA performingcommunication based on a bandwidth (or front-end) of 20 MHz or 40 MHz ina BSS (or AP) supporting a bandwidth (or front-end) of 80 MHz

Referring to FIG. 10, an STA supporting a bandwidth of 20 MHz or 40 MHzmay be located in a BSS (or basic service area (BSA)) supporting abandwidth of 80 MHz. In this case, in order to prevent interference frombeing experienced by the STA supporting the bandwidth of 20 MHz or 40MHz, part of the band for an OFDMA packet (or PPDU) that is beingtransmitted in the 80 MHz bandwidth may be used as a guard tone or DCtone for an STA having a front-end of 20 MHz or 40 MHz.

In order to use part of the frequency resource within the 80 MHzbandwidth as the guard tone or DC tone for the STA having a front-end of20 MHz or 40 MHz, among the resource units being allocated within the 80MHz bandwidth, a specific resource unit (e.g., IRU) (or frequencyresource), which corresponds to the position corresponding to the guardtone or DC tone for the STA supporting the bandwidth of 20 MHz or 40MHz, may be used as a guard tone or DC tone instead of being used as aresource for data transmission.

As shown in FIG. 10, in case a resource unit (RRU (or basic tone unitBTU), IRU (or small tone unit (STU)) is allocated within a bandwidth of80 MHz, among part of the resource units, part of the resource units(e.g., IRU) 1000 may be allocated to the regions of the DC tone 1020 andthe guard tones 1010 and 1030. More specifically, as shown in FIG. 10, aresource unit 1000 of the 80 MHz bandwidth, which corresponds to the DCtone and the guard tones of the bandwidth of 20 MHz, may be allocated tothe DC tone 1020 and the guard tones 1010 and 1030. Similarly, aresource unit of the 80 MHz bandwidth, which corresponds to the DC toneand the guard tones of the bandwidth of 40 MHz, may be allocated to theDC tone and the guard tones.

The above-described method for allocating the DC tone and the guardtones may also be similarly applied to a case when the BSS supports abandwidth (front-end) of 40 MHz and when an STA performing communicationbased on a bandwidth of 20 MHz within the corresponding BSS (or BSA)exists. In other words, in case a resource unit (RRU (or BTU), IRU (orSTU)) is allocated within a bandwidth of 40 MHz, among part of theresource units, part of the resource units (e.g., IRU) may be allocatedto the regions of the DC tone and the guard tones. More specifically, aresource unit of the 40 MHz bandwidth, which corresponds to the DC toneand the guard tones of the bandwidth of 20 MHz, may be allocated to theDC tone and the guard tones.

More specifically, in the present invention, a resource unit of a secondbandwidth, which corresponds to the DC tone and the guard tones of afirst bandwidth, may be allocated to the DC tone and the guard tonesinstead of the data tones. Herein, the second bandwidth may be largerthan the first bandwidth. Alternatively, in the present invention, aresource unit of a second bandwidth, which corresponds to the DC toneand the guard tones of a first bandwidth, may simply be not used.Alternatively, in the present invention, a frequency resource of asecond bandwidth, which corresponds to the DC tone and the guard tonesof a first bandwidth, may simply be not used. for simplicity in thedescription of the present invention, a case when a resource unit of asecond bandwidth, which corresponds to the DC tone and the guard tonesof a first bandwidth, will mostly be assumed herein.

Hereinafter, a resource unit, which is being used as a DC tone/guardtone for preventing interference instead of being used as a datatransmission resource (or data tone), may be expressed by the term DCtone transmission unit/guard tone transmission unit. Part of thefrequency resource that was used as a data tone, which is not dividedinto resource units for preventing interference, may also be used as theDC tone/guard tone.

According to the exemplary embodiment of the present invention, the APmay transmit information indicating that a specific resource unit isbeing used as DC tone/guard tone for preventing interference instead ofbeing used as data transmission resource (hereinafter, DC tone/guardtone allocation information) to the STA, which is included in the BSS.

FIG. 11 is a conceptual view illustrating a method for transmitting DCtone/guard tone allocation information according to an exemplaryembodiment of the present invention.

Referring to FIG. 11, by transmitting DC tone/guard tone allocationinformation 1100, the AP may indicate to the STA that a specificresource unit is being not used for data transmission in an environmentwhere STAs respectively supporting different bandwidths co-exist (or ina diverse BS capability environment).

The STA may receive the DC tone/guard tone allocation information 1100and may not transmit any channel feedback information on the frequencyband corresponding to DC tone transmission unit/guard tone transmissionunit. More specifically, since the DC tone transmission unit/guard tonetransmission unit is not being used for the data transmission performedby the AP/data transmission performed by the STA, the STA may nottransmit any separate feedback information on the DC tone transmissionunit/guard tone transmission unit.

Additionally, the RRU (BTU) and the IRU (STU) may be diversely locatedwithin the frequency band. The AP may allocate the RRU (BTU) and the IRU(STU) in diverse combinations within the frequency band. In this case,the positions of the DC tone transmission unit and the guard tonetransmission unit may be varied in accordance with the combination ofthe resource allocation. Therefore, the AP may transmit information onthe allocation of such resource units to the STA. The STA may determinewhich transmission unit (or frequency band) corresponds to the DC tonetransmission unit/guard tone transmission unit based on the informationon the allocation of resource units and the DC tone/guard toneallocation information 1100.

In the wireless LAN system, a method for allocating a resource unit inaccordance with the size of the bandwidth may be defined in advance, andthe method for allocating a resource unit in accordance with the size ofthe bandwidth may be defined as a specific indicator within a table,and, then, based on this indicator, the AP may transmit the informationon the allocation of resource units.

The above-described information on the allocation of resource unitsand/or DC tone/guard tone allocation information 1100 may be transmittedas general information to multiple STAs being included in the BSS basedon a signal field of the PPDU being transmitted by the AP (or may betransmitted based on broadcast).

More specifically, the AP may transmit the information on the allocationof resource units and/or the DC tone/guard tone allocation information1100 to the STAs being included in the BSS through a signal field (e.g.,HE-SIG 1 (or HE-SIG A)) transmitting general information.

For example, the DC tone/guard tone allocation information 1100 may beallocated to x bits of the signal field, and the x bits may indicatethat a specific resource unit (or specific band) (e.g., IRU) is beingused as the DC tone transmission unit/guard tone transmission unit. Atthis point, the size of x may be determined by a function that isrelated to the number of resource units.

Alternatively, in case STAs supporting 20 MHz and 40 MHz are included inthe BSS, the AP may also transmit information on the allocation ofresource units corresponding to the size of the bandwidth, which isbeing supported by the STAs. For example, the information on theallocation of the resource units may be allocated to 1 bit or 2 bits inan IRU allocation structure (i.e., as information indicating that thespecific IRU is not being used), which corresponds to the size of thebandwidth being supported by the STAs.

FIG. 12 is a conceptual view illustrating a tone allocation methodaccording to an exemplary embodiment of the present invention.

FIG. 12 discloses resource allocation within the entire bandwidth basedon the allocation of the DC tone transmission unit/guard tonetransmission unit, which is described above in FIG. 10 and FIG. 11. Itwill be assumed that the size of a minimum bandwidth (or front-end),which is supported by the STA, is equal to 20 MHz. Additionally, it willalso be assumed that the size of each of the different front-ends beingrespectively supported by each of the plurality of STAs is equal to 20MHz, 40 MHz, or 80 MHz. Moreover, the size of each of the differentfront-ends being respectively supported by each of the plurality of STAsmay also be extended to 80+80 MHz, 160 MHz, and so on. Theabove-described size of the minimum bandwidth being supported by the STAand the sizes of multiple bandwidths each being respectively supportedby multiple STAs are exemplary sizes. And, therefore, the sizes may bediversely configured to have different values, and such exemplaryembodiments of the present invention may also be included in the scopeof the present invention. Furthermore, cases when the RRU (also referredto as BTU) and the IRU (also referred to as STU) are used as theresource unit will also be assumed herein.

Basically, the allocation structure may be designed so that a DC tone islocated at the center of a bandwidth unit of 20 MHz and that left guardtone/right guard tone are located at both ends of the bandwidth.

More specifically, in a case when it is assumed that the DC tonetransmission unit/guard tone transmission unit corresponds to the IRU,the allocation structure may be designed to have a structure of leftguard tone/IRU/RRU/IRU/RRU/IRU/right guard tone in units of 20 MHz. Thisstructure may be applied by being scaled in accordance with the size ofthe bandwidth, thereby being applied to each of the bandwidth of 40 MHzand the bandwidth of 80 MHz.

Among the allocated resource units, the AP may determine whether to usethe IRU as the DC tone transmission unit/guard tone transmission unit orwhether to use the IRU as data tone for transmitting data. The AP maytransmit the determined result on whether or not to use the IRU as theDC tone transmission unit/guard tone transmission unit to the STA. Forexample, in case STAs supporting a plurality of bandwidths each beingdifferent from one another exists in the BSS, among the allocatedresource units, the AP may determine to use the IRU as the DC tonetransmission unit/guard tone transmission unit.

The above-described determined result of the AP on determining whetheror not to use the IRU as the DC tone transmission unit/guard tonetransmission unit may be transmitted to the STAs existing in the BSS asgeneral information through a signal field (e.g., HE-SIG A (or HE-SIG1)) (or may be transmitted based on a broadcast transmission).

Referring to FIG. 12, an exemplary resource allocation method forconfiguring a DC tone transmission unit/guard tone transmission unitwill be disclosed.

For example, the RRU may be allocated to 56 tones, and the IRU may beallocated to 7 tones. And, a 14-tone resource unit, which is configuredof a group of 2 IRUs, may also be allocated as the minimum resourceunit.

Referring to the left side of FIG. 12, for the bandwidth of 20 MHz, leftguard tone (6 tones)/IRU/RRU/RRU/IRU (this may be used as a DCtone)/RRU/RRU/IRU/right guard tone (5 tones) may be allocated.

Also, referring to the center of FIG. 12, for the bandwidth of 40 MHz,left guard tone (6 tones)/IRU/RRU/RRU/IRU (this may be used as a DC tonetransmission unit for the 20 MHz front-end)/RRU/RRU/IRU/DC (11 tones,this performs the function of a DC tone for the 40 MHz front-end orright guard tone (5 tones)+left guard tone (6 tones) for the 20 MHzfront-end)/IRU/RRU/RRU/IRU (this may be used as a DC tone transmissionunit for the 20 MHz front-end)/RRU/RRU/IRU/right guard tone (5 tones)may be allocated.

More specifically, in order to reduce interference on the STA, whichsupports the bandwidth of 20 MHz, a DC tone transmission unit (or DCtone)/guard tone transmission unit (or guard tone) may be used for eachof the two 20 MHz bandwidths included in the bandwidth of 40 MHz.

Also, referring to right side of FIG. 12, for the bandwidth of 80 MHz,left guard tone (6 tones)/IRU/RRU/RRU/IRU (this may be used as a DC tonetransmission unit for the 20 MHz front-end)/RRU/RRU/IRU/DC (11 tones,this performs the function of a DC tone for the 40 MHz front-end orright guard tone (5 tones)+left guard tone (6 tones) for the 20 MHzfront-end)/IRU/RRU/RRU/IRU (this may be used as a DC tone transmissionunit for the 20 MHz front-end)/RRU/RRU/IRU/DC (11 tones, this performsthe function of a DC tone for the 80 MHz front-end or right guard tone(5)+left guard tone (6) for the 40 MHz front-end)/IRU/RRU/RRU/IRU (thismay be used as a DC tone transmission unit for the 20 MHzfront-end)/RRU/RRU/IRU/DC (11 tones, this performs the function of a DCtone for the 40 MHz front-end or right guard tone (5 tones)+left guardtone (6 tones) for the 20 MHz front-end)/IRU/RRU/RRU/IRU (this may beused as a DC tone transmission unit for the 20 MHzfront-end)/RRU/RRU/IRU/right guard tone (5 tones) may be allocated.

In the combination according to each size of the above-described bands,the left guard tone/right guard tone and the DC tone may form othercombinations.

The following discloses yet another exemplary resource allocation methodfor configuring DC tone transmission unit/guard tone transmission unit.

For the bandwidth of 20 MHz, left guard tone (7 tones)/IRU/RRU/RRU/DCtone (5 tones)/RRU/RRU/IRU/right guard tone (6 tones) may be allocated.

For the bandwidth of 40 MHz, left guard tone (7 tones)/IRU/RRU/RRU/DC(this may be used as a DC tone transmission unit for the 20 MHzfront-end, 5 tones)/RRU/RRU/IRU/DC (13 tones, DC tone for the 40 MHzfront-end or right guard tone (6 tones)+left guard tone (7 tones) forthe 20 MHz front-end)/IRU/RRU/RRU/DC (this may be used as a DC tonetransmission unit for the 20 MHz front-end, 5 tones)/RRU/RRU/IRU/rightguard tone (6 tones) may be allocated.

For the bandwidth of 80 MHz, left guard tone (7 tones)/IRU/RRU/RRU/DC (5tones, this may be used as a DC tone transmission unit for the 20 MHzfront-end)/RRU/RRU/IRU/DC (13 tones, this performs the function of a DCtone for the 40 MHz front-end or right guard tone (6 tones)+left guardtone (7 tones) for the 20 MHz front-end)/IRU/RRU/RRU/DC (5 tones, thismay be used as a DC tone transmission unit for the 20 MHzfront-end)/RRU/RRU/IRU/DC (13 tones, this performs the function of a DCtone for the 80 MHz front-end or right guard tone (6 tones)+left guardtone (7 tones) for the 40 MHz front-end)/IRU/RRU/RRU/DC (this may beused as a DC tone transmission unit for the 20 MHzfront-end)/RRU/RRU/IRU/DC (13 tones, this performs the function of a DCtone for the 40 MHz front-end or right guard tone (6 tones)+left guardtone (7 tones) for the 20 MHz front-end)/IRU/RRU/RRU/DC (this may beused as a DC tone transmission unit for the 20 MHzfront-end)/RRU/RRU/IRU/right guard tones (6 tones) may be allocated.

Depending upon how the combined front-ends are combined, the wirelessresource being allocated to the DC tone transmission unit (or DCtone)/guard tone transmission unit (or guard tone) may also be used fordata transmission.

According to the exemplary embodiment of the present invention, aplurality of resource units may be combined so as to configure anotherresource unit, and another resource unit, which is configured by thecombination of a plurality of resource units, may be used as oneresource unit. Hereinafter, another resource unit that is configured bythe combination of a plurality of resource units may also be expressedby using the term logical combination resource unit.

For example, a plurality of IRUs may be combined to configure onelogical combination resource unit having the same size as the size of aRRU. In case an IRU size is equal to 14 tones, and if one logicalcombination resource unit is configured by grouping 4 IRUs, one logicalcombination resource unit may correspond to 56 tones. And, 56 tones maycorrespond to the RRU size.

Additionally, two RRUs of 56 tones may be grouped (or combined) so as toconfigure one logical combination resource unit corresponding to 112tones. The one logical combination resource unit corresponding to 112tones may be collectively interleaved or interleaving may be performedon each of the two 56-tone RRUs.

Alternatively, two 56-tone RRUs and at least one 14-tone IRU may begrouped (or combined) to configured one logical combination resourceunit corresponding to 114 tones. In case two 56-tones RRUs and at leastone IRU is grouped, this may be equal to 126 tones. Among the 126 tones,only 114 tones may be used for configuring the logical combinationresource unit, and the remaining (or leftover) 14 tones may not be used.Since the 114 tones corresponds to a size that is the same as theresource unit that was used in the legacy wireless LAN system, thelegacy pilot allocation and interleaving method may be used. Forexample, among the 114 tones, pilot tones may be allocated to 6 tones,and data tones may be allocated to the remaining 108 tones. For the datatones of 108 tones, an interleaving process that is based on a 108-sizeinterleaver may be performed.

Alternatively, one logical combination resource unit corresponding to224 tones may be configured based on a grouping (or combination) of four56-tone RRUs. Interleaving that is based on one interleaver may beperformed on the logical combination resource unit corresponding 224tones, or interleaving may be separately performed on each resource unitcorresponding to 56 tones. In case interleaving is separately performedon each of the individual resource units corresponding to 56 tones, a4-block interleaving may be used based on a 52-size interleaver.

Alternatively, one logical combination resource unit corresponding to242 tones may be configured based on a combination of four 56-tone RRUsand three IRUs. Among the tones (266 tones) configured by thecombination of the four 56-tone RRUs and the three IRUs, with theexception for the 242 tones for the logical combination resource unit,the remaining 24 tones may not be used. Since the 242 tones correspondsto a size that is the same as the resource unit that was used in thelegacy wireless LAN system, the legacy pilot allocation and interleavingmethod may be used. For example, among the 242 tones, pilot tones may beallocated to 8 tones, and data tones may be allocated to the remaining234 tones. For the data tones of 234 tones, an interleaving process thatis based on a 234-size interleaver may be performed.

Alternatively, in case of allocating a size that is larger than 242tones to the logical combination resource unit, tones corresponding to amultiple of the 242 tones may be allocated to the logical combinationresource unit. For example, in a bandwidth of 80 MHz, one logicalcombination resource unit corresponding to 484 tones, which is equal to2 times the size of 242 tones, may be used.

FIG. 13 is a conceptual view illustrating a tone allocation methodaccording to an exemplary embodiment of the present invention.

FIG. 13 discloses an allocation of resource units based on the DC tonetransmission unit/guard tone transmission unit, in a case when the RRUsize is equal to 114 tones and the IRU size is equal to 7 tones. TwoIRUs may be grouped (or combined) to be configured and used as onelogical combination resource unit.

Referring to the left side of FIG. 13, for the 40 MHz bandwidth, leftguard tone (6 tones)/IRU/RRU/IRU (this may be used as a DC tonetransmission unit for the 20 MHz front-end)/RRU/IRU/DC (DC tone for the40 MHz front-end, 3 tones)/IRU/RRU/IRU (this may be used as a DC tonetransmission unit for the 20 MHz front-end)/RRU/IRU/right guard tone (5tones) may be allocated.

Referring to the right side of FIG. 13, for the 80 MHz bandwidth, leftguard tone (6 tones)/IRU/RRU/IRU (this may be used as a DC tonetransmission unit for the 20 MHz front-end)/RRU/IRU/DC (this may be usedas a DC tone transmission unit for the 40 MHz front-end, 3tones)/IRU/RRU/IRU (this may be used as a DC tone transmission unit forthe 20 MHz front-end)/RRU/IRU/DC (11 tones, this performs the functionof a tone for the 80 MHz front-end or right guard tone (5 tones)+leftguard tone (6 tones) for the 40 MHz front-end))/IRU/RRU/IRU (this may beused as a DC tone transmission unit for the 20 MHz front-end)/RRU/IRU/DC(this may be used as a DC tone transmission unit for the 40 MHzfront-end, 3 tones)/IRU/RRU/IRU (this may be used as a DC tonetransmission unit for the 20 MHz front-end)/RRU/IRU/right guard tone (5tones) may be allocated.

Depending upon how the combined front-ends are combined, the wirelessresource being allocated to the DC tone transmission unit (or DCtone)/guard tone transmission unit (or guard tone) may also be used fordata transmission. In the above-described combination according to thebandwidth, other combinations of the left guard tone, right guard tone,and DC tone may also be configured as described below.

For the 40 MHz bandwidth, left guard tone (6 tones)/IRU/RRU/DC (5 tones,this may be used as a DC tone transmission unit for the 20 MHzfront-end)/RRU/IRU/DC (7 tones, this may be used as a DC tonetransmission unit for the 40 MHz front-end)/IRU/RRU/DC (5 tones, thismay be used as a DC tone transmission unit for the 20 MHzfront-end)/RRU/IRU/right guard tone (5 tones) may be allocated.

For the 80 MHz bandwidth, left guard tone (6 tones)/IRU/RRU/DC (5 tones,this may be used as a DC tone transmission unit for the 20 MHzfront-end)/RRU/IRU/DC (7 tones, this may be used as a DC tonetransmission unit for the 40 MHz front-end)/IRU/RRU/DC (5 tones, thismay be used as a DC tone transmission unit for the 20 MHzfront-end)/RRU/IRU/DC (11 tones, this performs the function of a DC tonefor the 80 MHz front-end or right guard tone (5 tones)+left guard tone(6 tones) for the 40 MHz front-end)/IRU/RRU/DC (5 tones, this may beused as a DC tone transmission unit for the 20 MHz front-end)/RRU/IRU/DC(7 tones, this may be used as a DC tone transmission unit for the 40 MHzfront-end)/IRU/RRU/DC (3 tones, this may be used as a DC tonetransmission unit for the 20 MHz front-end)/RRU/IRU/right guard tone (5tones) may be allocated.

Depending upon how the combined front-ends are combined, the wirelessresource being allocated to the DC tone transmission unit (or DCtone)/guard tone transmission unit (or guard tone) may also be used fordata transmission. In the above-described combination according to thebandwidth, other combinations of the left guard tone, right guard tone,and DC tone may also be configured as shown in FIG. 13.

In case the RRU size is equal to 114 tones, two RRUs may be grouped (orcombined) to configure one logical combination resource unitcorresponding to 228 tones. The logical combination resource unitcorresponding to 228 tones may be collectively interleaved orinterleaving may be separately performed for each RRUs corresponding to114 tones.

Additionally, one logical combination resource unit corresponding to 242tones may be defined by grouping (or combining) two RRUs and two IRUs.Remaining tones may not be used. Since the 242 tones corresponds to asize that is the same as the resource unit that was used in the legacywireless LAN system, the legacy pilot allocation and interleaving methodmay be used. For example, among the 242 tones, pilot tones may beallocated to 8 tones, and data tones may be allocated to the remaining234 tones. For the data tones of 234 tones, an interleaving process thatis based on a 234-size interleaver may be performed.

Alternatively, in case of allocating a size that is larger than 242tones to the logical combination resource unit, tones corresponding to amultiple of the 242 tones may be allocated to the logical combinationresource unit. For example, in a bandwidth of 80 MHz, one logicalcombination resource unit corresponding to 484 tones, which is equal to2 times the size of 242 tones, may be used.

FIG. 14 is a conceptual view illustrating a PPDU format according to anexemplary embodiment of the present invention.

FIG. 14 discloses a PPDU format according to the exemplary embodiment ofthe present invention.

Referring to the upper part of FIG. 14, a PPDU header of a downlink PPDUmay include a legacy-short training field (L-STF), a legacy-longtraining field (L-LTF), a legacy-signal (L-SIG), a highefficiency-signal A (HE-SIG A), a high efficiency-short training field(HE-STF), a high efficiency-long training field (HE-LTF), and a highefficiency-signal B (HE-SIG B). The PPDU may be divided into a legacypart, which consists of a part starting from the PHY header to theL-SIG, and a high efficiency (HE) part, which consists of a part afterthe L-SIG.

The L-STF 1400 may include a short training orthogonal frequencydivision multiplexing (OFDM) symbol. The L-STF 1400 may be used forframe detection, automatic gain control (AGC), diversity detection, andcoarse frequency/time synchronization.

The L-LTF 1410 may include a long training orthogonal frequency divisionmultiplexing (OFDM) symbol. The L-LTF 1410 may be used for finefrequency/time synchronization and channel prediction.

The L-SIG 1420 may be used for transmitting control information. TheL-SIG 1420 may include information on data transmission rate, datalength, and so on.

The HE-SIG A 1430 may also include information STA for indicating a STAthat is to receive the PPDU. For example, the HE-SIG A 1430 may includean identifier of a specific STA (or AP) that is to receive the PPDU andinformation for indicating a group of the specific STA. Also, in casethe PPDU is transmitted based on the OFDMA or MIMO, the HE-SIG A 1430may also include resource allocation information corresponding to theSTA.

Additionally, the HE-SIG A 1430 may also include color bits informationfor BSS identification information, bandwidth information, tail bit, CRCbit, modulation and coding scheme (MCS) information on the HE-SIG B1460, information on the number of symbols for the HE-SIG B 1460, andcyclic prefix (CP) (or guard interval (GI)) length information.

The HE-SIG A 1430 may also be expressed by the term HE-SIG 1 (or aprimary signal field).

The HE-STF 1440 may be used for enhancing automatic gain controlestimation in a multiple input multiple output (MIMO) environment or anOFDMA environment.

The HE-LTF 1450 may be used for estimating a channel in a MIMOenvironment or an OFDMA environment.

The HE-SIG B 1460 may include information on a length modulation andcoding scheme (MCS) of a physical layer service data unit (PSDU) foreach STA and a tail bit, and so on. Additionally, the HE-SIG B 1460 mayalso include information on the STA that is to receive the PPDU andOFDMA-based resource allocation information (or MU-MIMO information). Incase the OFDMA-based resource allocation information (or MU-MIMO relatedinformation) is included in the HE-SIG B 1460, resource allocationinformation may not be included in the HE-SIG A 1430.

The HE-SIG B 1460 may also be expressed by the term HE-SIG 2 (or asecondary signal field).

According to the exemplary embodiment of the present invention, asdescribed above, in case a resource allocation signaling bitmapincluding the resource allocation information is transmitted from theHE-SIG B 1460, the above-described resource allocation signaling bitmapinterpretation information may be transmitted from the HE-SIG A 1430,which is transmitted before the HE-SIG B 1460. In case the resourceallocation signaling bitmap interpretation information is transmittedthrough the HE-SIG A 1430, the decoding complexity of the resourceallocation signaling bitmap that is transmitted through the HE-SIG B1460 may be reduced. Alternatively, the resource allocation signalingbitmap interpretation information and the resource allocation signalingbitmap may both be transmitted to the HE-SIG B 1460, and, whenperforming information parsing, the resource allocation signaling bitmapinterpretation information is decoded firsthand within the HE-SIG B1460. Thereafter, the resource allocation signaling bitmap may bedecoded based on the decoded bitmap interpretation information.

The IFFT size being applied to the HE-STF 1440 and the field after theHE-STF 1440 may be different from the IFFT size being applied to thefield before the HE-STF 1440. For example, the IFFT size being appliedto the HE-STF 1440 and the field after the HE-STF 1440 may be 4 timeslarger than the IFFT size being applied to the field before the HE-STF1440. The STA may receive the HE-SIG A 1430 and may receive indicationto receive the downlink PPDU based on the HE-SIG A 1430. In this case,the STA may perform decoding based on the FFT size, which is changedstarting from the HE-STF 1440 and the field after the HE-STF 1440.Conversely, in case the STA fails to receive indication to receive thedownlink PPDU based on the HE-SIG A 1430, the STA may stop the decodingprocess and may perform network allocation vector (NAV) configuration. Acyclic prefix (CP) of the HE-STF 1440 may have a size that is largerthan the CP of other fields, and, during such CP period, the STA maychange the FFT size and may perform decoding on the downlink PPDU.

The order of the fields configuring the format of the PPDU shown in theupper part of FIG. 14 may also be changed. For example, as shown in themiddle part of FIG. 14, the HE-SIG B 1415 may be positioned immediatelyafter the HE-SIG A 1405. The STA may perform decoding up to the HE-SIG A1405 and the HE-SIG B 1415 and may receive the required controlinformation and may then perform NAV configuration. Similarly, the IFFTsize being applied to the HE-STF 1425 and the field after the HE-STF1425 may be different from the IFFT size being applied to the fieldbefore the HE-STF 1425.

The STA may receive the HE-SIG A 1405 and the HE-SIG B 1415. In case thereception of the PPDU is indicated based on the HE-SIG A 1405, the STAmay change the FFT size starting from the HE-STF 1425 and may thenperform decoding on the PPDU. Conversely, the STA may receive the HE-SIGA 1405, and, in case the reception of the downlink PPDU is not indicatedbased on the HE-SIG A 1405, the network allocation vector (NAV)configuration may be performed.

Referring to the lower part of FIG. 14, a PPDU format for the downlink(DL) multi-user (MU) OFDMA transmission is disclosed. According to theexemplary embodiment of the present invention, the AP may transmit adownlink frame or downlink PPDU by using a PPDU format for DL MU OFDMAtransmission. Each of the plurality of downlink PPDUs may be transmittedto each of the plurality of STAs through different transmissionresources (frequency resources or spatial streams). In the PPDU, aprevious field of the HE-SIG B 1445 may be transmitted from transmissionresources each being different from one another in a duplicated format.In case of the HE-SIG B 1445, the HE-SIG B 1445 being transmitted fromsome of the subchannels (e.g., subchannel1, subchannel2) may correspondto an independent field including individual information, and the HE-SIGB 1445 being transmitted from the remaining subchannels (e.g.,subchannel3, subchannel4) may correspond to a duplicated format of theHE-SIG B 1445 being transmitted from other subchannels (e.g.,subchannel1, subchannel2). Alternatively, the HE-SIG B 1445 may betransmitted in an encoded format from the entire transmission resources.The fields after the HE-SIG B 1445 may include separate information foreach of the plurality of STAs receiving the PPDU.

For example, the HE-SIG A 1435 may include identification information onthe plurality of STAs that are to receive downlink data and informationon the channels to which the downlink data of the plurality of STAs aretransmitted.

In case each of the fields included in the PPDU is transmitted througheach transmission resource, the CRC for each field may be included inthe PPDU. Conversely, in case a specific field included in the PPDU isencoded and transmitted over the entire transmission resource, the CRCfor each field may not be included in the PPDU. Therefore, the overheadfor the CRC may be reduced.

Similarly, in the PPDU format for the DL MU transmission, the HE-STF1455 and the field after the HE-STF 1455 may also be encoded based on anIFFT size that is different from the field before the HE-STF 1455.Therefore, in case the STA receives the HE-SIG A 1435 and the HE-SIG B1445 and receives an indication on the reception of the PPDU based onthe HE-SIG A 1435, the STA may change the FFT size starting from theHE-STF 1455 and may then perform decoding on the PPDU.

FIG. 15 is a block view illustrating a wireless device to which theexemplary embodiment of the present invention can be applied.

Referring to FIG. 15, as an STA that can implement the above-describedexemplary embodiment, the wireless device 1500 may correspond to an AP1500 or a non-AP station (STA) 1550.

The AP 1500 includes a processor 1510, a memory 1520, and a radiofrequency (RF) unit 1530.

The RF unit 1530 is connected to the processor 1510, thereby beingcapable of transmitting and/or receiving radio signals.

The processor 1510 implements the functions, processes, and/or methodsproposed in the present invention. For example, the processor 1510 maybe implemented to perform the operations of the AP according to theabove-described exemplary embodiments of the present invention. Theprocessor may perform the operations of the AP, which are disclosed inthe exemplary embodiments of FIG. 1 to FIG. 14.

For example, the processor 1510 may be configured to allocate each ofthe plurality of wireless resources for each of the plurality ofstations (STAs) being included in the basic service set (BSS) within theentire bandwidth and to transmit each of the plurality of wirelessresources to each of the plurality of STAs through a physical protocoldata unit (PPDU). Each of the plurality of wireless resources maycorrespond to a combination of a plurality of wireless resource unitsthat are each defined to have a different size within the frequencyaxis. Additionally, each of the plurality of wireless resources may bedetermined by considering the bandwidth size of at least one STA, amongthe plurality of STAs, wherein the at least one STA supports a bandwidthhaving a size that is smaller than that of the entire bandwidth. At thispoint, each of the plurality of wireless resources may be determinedwith the exception for a direct current (DC) tone transmission unit anda guard tone transmission unit within the entire bandwidth. The DC tonetransmission unit may correspond to a wireless resource unitcorresponding to the position of a DC tone within the bandwidth of atleast one STA. And, the guard tone transmission unit may correspond to awireless resource unit corresponding to the position of a guard tonewithin the bandwidth of at least one STA. The DC tone transmission unitand the guard tone transmission unit may be varied in accordance withthe bandwidth size of at least one STA. The PPDU that is beingtransmitted by the AP may include information on the DC tonetransmission unit and the guard tone transmission unit.

The plurality of wireless resource units configuring the plurality ofwireless resources being allocated to the plurality of STAs by the APmay include a primary wireless resource unit and a secondary wirelessresource unit. The number of tones being allocated to the primarywireless resource unit may be larger than the number of tones beingallocated to the secondary wireless resource unit. Each of the pluralityof wireless resources being allocated to the plurality of STAs by the APmay include one logical combination resource unit, which is definedbased on a combination of at least one primary wireless resource unitand at least one secondary wireless resource unit.

The STA 1450 includes a processor 1460, a memory 1470, and a radiofrequency (RF) unit 1480.

The RF unit 1480 is connected to the processor 1460, thereby beingcapable of transmitting and/or receiving radio signals.

The processor 1460 implements the functions, processes, and/or methodsproposed in the present invention. For example, the processor 1460 maybe implemented to perform the operations of the STA according to theabove-described exemplary embodiments of the present invention. Theprocessor may perform the operations of the STA, which are disclosed inthe exemplary embodiments of FIG. 1 to FIG. 14.

For example, the processor 1560 may be configured to acquire informationon the DC tone transmission unit and the guard tone transmission unitand to determine the resource being allocated for the STA. Additionally,the processor 1560 may be configured to transmit in advance informationon a supportable bandwidth (or front-end) to the AP for resourceallocation.

The processor 1510 and 1560 may include an application-specificintegrated circuit (ASIC), another chip set, a logical circuit, a dataprocessing device, and/or a converter converting a baseband signal and aradio signal to and from one another. The memory 1520 and 1570 mayinclude a read-only memory (ROM), a random access memory (RAM), a flashmemory, a memory card, a storage medium, and/or another storage device.The RF unit 1530 and 1580 may include one or more antennas transmittingand/or receiving radio signals.

When the exemplary embodiment is implemented as software, theabove-described method may be implemented as a module (process,function, and so on) performing the above-described functions. Themodule may be stored in the memory 1520 and 1570 and may be executed bythe processor 1510 and 1560. The memory 1520 and 1570 may be locatedinside or outside of the processor 1510 and 1560 and may be connected tothe processor 1510 and 1560 through a diversity of well-known means.

What is claimed is:
 1. A method for allocating wireless resources in awireless local area network (WLAN), comprising: receiving, by a station(STA), a physical protocol data unit (PPDU) from an access point (AP),wherein the PPDU is received based on a resource unit addressed to theSTA among a plurality of resource units corresponding to the entirebandwidth of the PPDU, wherein the plurality of resource units areallocated based on orthogonal frequency division multiple access(OFDMA), wherein the plurality of resource units comprise a basic toneunit (BTU) and a small tone unit (STU) having a number of tones beingless than that of the BTU; and wherein when two STUs are allocatedadjacent to direct current (DC) tones of the entire bandwidth, the twoSTUs are defined as a logical resource unit.
 2. The method of claim 1,wherein a first STU of the two STUs is allocated contiguous to the DCtones which are allocated contiguous to a second STU of the two STUs. 3.The method of claim 1, wherein when a plurality of BTUs are allocated,the plurality of BTUs are allocated adjacent to left guard tones andright guard tones of the entire bandwidth.
 4. The method of claim 1,wherein each STU has 13 tones, wherein the entire bandwidth is one of 20MHz, 40 MHz, 80 MHz, and 160 MHz.
 5. The method of claim 1, whereinallocation location of the BTU and the STU is signaled by a signal fieldincluded in a header of the PPDU.
 6. The method of claim 1, wherein aheader included in the PPDU includes information on whether the logicalresource unit is addressed to the STA.
 7. A station (STA) for allocatingwireless resources in a wireless local area network (WLAN), comprising:a radio frequency (RF) unit transmitting and/or receiving radio signals;and a processor being operatively connected to the RF unit, wherein theprocessor is configured: to receive a physical protocol data unit (PPDU)from an access point (AP), wherein the PPDU is received based on aresource unit addressed to the STA among a plurality of resource unitscorresponding to the entire bandwidth of the PPDU, wherein the pluralityof resource units are allocated based on orthogonal frequency divisionmultiple access (OFDMA), wherein the plurality of resource unitscomprise a basic tone unit (BTU) and a small tone unit (STU) having anumber of tones being less than that of the BTU; and wherein when twoSTUs are allocated adjacent to direct current (DC) tones of the entirebandwidth, the two STUs are defined as a logical resource unit.
 8. TheSTA of claim 7, wherein a first STU of the two STUs is allocatedcontiguous to the DC tones which are allocated contiguous to a secondSTU of the two STUs.
 9. The STA of claim 7, wherein when a plurality ofBTUs are allocated, the plurality of BTUs are allocated adjacent to leftguard tones and right guard tones of the entire bandwidth.
 10. The STAof claim 7, wherein each STU has 13 tones, wherein the entire bandwidthis one of 20 MHz, 40 MHz, 80 MHz, and 160 MHz.
 11. The STA of claim 7,wherein allocation location of the BTU and the STU is signaled by asignal field included in a header of the PPDU.
 12. The STA of claim 7,wherein a header included in the PPDU includes information on whetherthe logical resource unit is addressed to the STA.